JP2020030427A - Optical body and window material - Google Patents

Abstract

To provide an optical body which offers superior anti-glare performance and visibility.SOLUTION: An optical body with a fine rugged layer is provided. In a 35.3×26.5 μm rectangular area of a fine rugged surface, an arithmetic average roughness Ra is 0.2 μm or less, and an average length RSm of roughness curve elements is 10 μm or less, or a ratio of a surface area to area of the rectangular area is in a range of 1.04 to 1.5, inclusive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical body and a window material, and more specifically, to an optical body having both high antiglare property and viewability, and a window material including the same.

  In recent years, in buildings including high-rise buildings and tower condominiums, so-called reflected light pollution, which reflects light on window glasses and the like, and causes dazzling to users of other nearby buildings, is a frequent problem. It has become. Therefore, when constructing a building, it is required to take sufficient measures against the reflected light pollution described above.

  Here, as a measure against glare of the reflected light from the window glass of the building, for example, there is a method of directly blocking the reflected light by installing a louver or the like on the wall surface of the building. However, the installation of louvers is often avoided by the owner because the construction is large and the cost is high and the design of the building is affected.

  On the other hand, as a method of improving the antiglare property of a window glass of a building, there is a method of improving a reflection characteristic by attaching a film to the window glass in addition to the above-described method.

  For example, as a film capable of improving reflection characteristics including anti-glare properties, Patent Document 1 discloses a method of forming an AG (anti-glare) layer having a random uneven surface using a UV-curable resin on a substrate film, and forming the AG (anti-glare) layer on the base film. By forming a layer made of a low-refractive-index resin so as to flatten the shape, it is possible to obtain an optical film that can make black visible when attached to a display while flattening the reflectance in the visible light range. Is disclosed.

  In addition, Patent Document 2 discloses a method in which, when a film is obtained by transfer-molding irregularities on a mold surface using a UV-curable resin on a base film to obtain a film, a mold surface on which blast particles having a predetermined particle size are struck is used. This discloses that a film with reduced glare can be obtained while maintaining high transmission definition.

International Publication 2015/071943 JP-A-2006-012095

  However, any of the above-mentioned conventional films is mainly used for a polarizing plate provided on a display surface of a liquid crystal panel such as a personal computer or a liquid crystal television. All of the above-mentioned conventional films have room for improvement from the viewpoint of achieving both high anti-glare properties and high viewability when used for window glass.

  An object of the present invention is to solve the above-described various problems in the related art and achieve the following objects. That is, an object of the present invention is to provide an optical body having excellent antiglare properties and viewability, and a window material having excellent antiglare properties and viewability.

  The present inventors have intensively studied to achieve the above object without limiting to a film. As a result, it has been found that by optimizing the characteristics of the roughness of the fine uneven surface, it is possible to achieve both high antiglare property and high viewability, and the present invention has been completed.

The present invention is based on the above findings by the present inventors, and the means for solving the above problems are as follows. That is,
<1> An optical body including a fine unevenness layer,
In a rectangular area of 35.3 μm × 26.5 μm on the fine uneven surface,
Arithmetic mean roughness Ra is 0.2 μm or less; and
The average length RSm of the roughness curve element is 10 μm or less, or the ratio of the surface area to the area of the rectangle is 1.04 or more and 1.5 or less;
An optical body characterized in that:

<2> further comprising a first transparent inorganic layer and a second transparent inorganic layer,
The optical body according to <1>, wherein the first transparent inorganic layer is arranged on a fine uneven surface of the fine uneven layer, and the second transparent inorganic layer is arranged on the first transparent inorganic layer. is there.

<3> the first transparent inorganic layer contains at least one of ZnO and CeO ₂ ,
The optical body according to <2>, wherein the second transparent inorganic layer contains at least one of SiO ₂ , SiN, SiON, and MgF ₂ .

<4> The total haze is 15% or more and 60% or less, the internal haze is 4% or less, the gloss at a measurement angle of 20 ° is 40 or less, and the transmitted image clarity at an optical comb width of 2 mm is 50. % Of the optical body according to any one of the above items <1> to <3>.

<5> The optical body according to any one of <2> to <4>, further including a third transparent inorganic layer on the second transparent inorganic layer.

<6> A window material including a glass substrate and the optical body according to any one of <1> to <5>.

  According to the present invention, it is possible to solve the conventional problems and achieve the object, and provide an optical body having excellent antiglare properties and viewability, and a window material having excellent antiglare properties and viewability. be able to.

FIG. 1 is a schematic cross-sectional view illustrating a configuration example of an optical body according to an embodiment of the present invention. It is a mimetic diagram showing an example method for forming a fine unevenness layer of an optical object concerning one embodiment of the present invention. FIG. 1 is a schematic cross-sectional view illustrating a configuration example of an optical body according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view illustrating a configuration example of an optical body according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view illustrating a configuration example of an optical body according to an embodiment of the present invention. It is a schematic cross section showing an example of composition of a window material concerning one embodiment of the present invention. It is a schematic cross section showing an example of composition of a window material concerning one embodiment of the present invention. It is a schematic cross section showing an example of composition of a window material concerning one embodiment of the present invention.

(Optical body)
As shown in FIG. 1, an optical body (hereinafter, sometimes referred to as “optical body according to the present embodiment”) 60 according to an embodiment of the present invention includes at least a fine uneven layer 63. In addition, the optical body according to the present embodiment can further include a first transparent inorganic layer, a second transparent inorganic layer, a third transparent inorganic layer, an antifouling coat layer, and other layers as necessary.

<Fine irregularities layer>
The fine uneven layer is a layer having a fine uneven structure on at least one surface. This uneven structure may be formed in a regular pattern or may be formed randomly.

The surface of the fine unevenness in the fine unevenness layer has an arithmetic mean roughness Ra of 0.2 μm or less in a rectangular region of 35.3 μm × 26.5 μm. In the fine uneven surface of the fine uneven layer, the average length RSm of the roughness curve element is 10 μm or less in the rectangular region, or the area of the rectangle (that is, 35.3 μm × 26.5 μm = 935). ratio of surface area to .45μm ²⁾ (μm ²⁾ (hereinafter sometimes referred to as "specific surface area".) is 1.04 to 1.5. The present inventors have surprisingly set the average length RSm and / or the specific surface area of the roughness curve element within the above-mentioned range while keeping the arithmetic average roughness Ra of the fine uneven surface at 0.2 μm or less. As a result, irregularities having a shape smaller than the wavelength of the visible light region can be formed, and some light can be transmitted without changing the traveling direction, and the transmitted image clarity can be increased, and anti-glare properties and viewability can be improved. Was found to be obtained.

  Further, the fine uneven surface in the fine uneven layer has an average length RSm of the roughness curve element of 10 μm or less and a specific surface area of 1.04 or more and 1.5 from the viewpoint of further improving the antiglare property and the viewability. The following is preferred.

  The arithmetic average roughness Ra of the fine unevenness surface in the fine unevenness layer is preferably 0.18 μm or less, more preferably 0.14 μm or less, from the viewpoint of achieving both higher antiglare property and viewability. preferable. On the other hand, the arithmetic average roughness Ra of the fine unevenness surface in the fine unevenness layer is preferably 0.08 μm or more, and more preferably 0.09 μm or more, from the viewpoint of further improving the antiglare property.

  In addition, the average length RSm of the roughness curve element on the fine uneven surface in the fine uneven layer is preferably 6 μm or less from the viewpoint of further enhancing the clearness of the transmitted image. In addition, the average length RSm of the roughness curve element of the fine unevenness surface in the fine unevenness layer is 2 μm or more from the viewpoint of achieving higher antiglare properties and viewability, and from the viewpoint of increasing the physical strength of the fine unevenness. Preferably, there is.

  Further, the specific surface area of the fine uneven surface in the fine uneven layer is preferably 1.1 or more from the viewpoint of further improving the antiglare property. In addition, the specific surface area of the fine uneven surface in the fine uneven layer is preferably 1.4 or less from the viewpoint of further improving the viewability.

  The above-mentioned Ra, RSm and specific surface area can be measured by the method used in the examples.

  Here, the fine concavo-convex layer can be formed by, for example, a shape transfer method, a phase separation method, a filler dispersion method, or the like. Hereinafter, as an example, a method of forming a fine uneven layer by a shape transfer method will be described with reference to FIG.

  FIG. 2 is a schematic diagram illustrating a shape transfer method, which is an example of a method for forming a fine uneven layer of the optical body according to the present embodiment. The shape transfer device 1 shown in FIG. 2 includes a master 2, a substrate supply roll 51, a take-up roll 52, guide rolls 53 and 54, a nip roll 55, a peeling roll 56, a coating device 57, and a light source. 58.

  The base material supply roll 51 is a roll in which a sheet-shaped base material 61 is wound in a roll shape, and the take-up roll 52 takes up a base material 61 on which a resin layer 62 to which the fine uneven structure 23 is transferred is laminated. Roll. The guide rolls 53 and 54 are rolls for transporting the base material 61. The nip roll 55 is a roll for bringing the base material 61 on which the resin layer 62 is laminated into close contact with the cylindrical master 2. The peeling roll 56 is used for transferring the fine uneven structure 23 to the resin layer 62. Reference numeral 62 denotes a roll for peeling the laminated base material 61 from the master 2. Here, the base material 61 can be, for example, a plastic base material such as a PET resin or a polycarbonate resin, and can be a plastic transparent film.

  The application device 57 includes an application unit such as a coater, and applies a composition containing an ultraviolet curable resin (ultraviolet curable resin composition) to the base material 61 to form a resin layer 62. The coating device 57 may be, for example, a gravure coater, a wire bar coater, a die coater, or the like. The light source 58 is a light source that emits ultraviolet light, and may be, for example, an ultraviolet lamp.

  The ultraviolet curable resin is a resin whose fluidity is reduced and hardened by irradiation with ultraviolet rays, and specific examples include an acrylic resin. In addition, the ultraviolet curable resin composition may contain an initiator, a filler, a functional additive, a solvent, an inorganic material, a pigment, an antistatic agent, a sensitizing dye, and the like, as necessary.

In the shape transfer device 1, first, a sheet-shaped substrate 61 is continuously fed from a substrate supply roll 51 via a guide roll 53. The ultraviolet curable resin composition is applied to the sent base material 61 by a coating device 57, and a resin layer 62 is laminated on the base material 61. Further, the base material 61 on which the resin layer 62 is laminated is brought into close contact with the master 2 by the nip roll 55. Thus, the fine uneven structure 23 formed on the outer peripheral surface of the master 2 is transferred to the resin layer 62. After the transfer of the fine concavo-convex structure 23, the resin layer 62 is cured by irradiation with light from the light source 58. Subsequently, the base material 61 on which the cured resin layer 62 is laminated is peeled off from the master 2 by a peeling roll 56, and is wound up by a winding roll 52 via a guide roll 54.
With such a shape transfer device 1, a fine uneven layer having a fine uneven surface can be continuously formed. Here, Ra, RSm and the specific surface area of the fine uneven surface can be adjusted, for example, by appropriately changing the fine uneven structure 23 of the master 2.

  In the shape transfer method described above, a base material and an ultraviolet-curable resin are prepared, and a fine uneven layer is formed on the base material using the resin (that is, as shown in FIG. The layer 63 is composed of a base material 61 and a resin layer 62 having a fine uneven structure. However, the fine uneven layer of the optical body of the present invention is not limited thereto. For example, an ultraviolet curable resin or a thermosetting resin Alternatively, a fine uneven structure may be directly formed on a base material made of a resin such as the above (ie, as shown in FIG. 3, the fine uneven layer 63 is formed only of the base material 61).

<First transparent inorganic layer>
As shown in FIG. 4, the optical body 60 according to the present embodiment preferably includes the first transparent inorganic layer 64 on the fine uneven surface of the fine uneven layer 63. The first transparent inorganic layer 64 has transparency and can have, for example, a function of absorbing light of a predetermined wavelength. The first transparent inorganic layer 64 can be formed by, for example, a sputtering method or a CVD method.
In this specification, "transparent" or "having transparency" means that a transmitted image has high definition and an image can be clearly recognized through an optical body.

The main component of the first transparent inorganic layer is preferably an inorganic compound having a band gap of 2.8 eV to 4.8 eV. Here, the band gap represents the wavelength at the absorption edge, and broadly indicates that light having a wavelength lower than the wavelength corresponding to the band gap is absorbed and light having a wavelength equal to or more than the wavelength corresponding to the band gap is transmitted. The above band gap of 2.8 eV or more and 4.8 eV or less is obtained by using the Planck constant (6.626 × 10 ⁻³⁴ J · s) and the light speed (2.998 × 10 ⁸ m / s). From the relational expression between the wavelength λ and the band gap energy E: “λ (nm) = 1240 / E (eV)”, the absorption edge is approximately within the range from 260 nm to 440 nm, which is the boundary between the ultraviolet region and the visible region. This indicates that there is a wavelength. Therefore, by using the above-mentioned inorganic compound for the first transparent inorganic layer, it is possible to achieve both transparency and ultraviolet absorption characteristics. From the same viewpoint, the main component of the first transparent inorganic layer is more preferably an inorganic compound having a band gap of 3.0 eV to 3.7 eV (approximately 340 nm to 420 nm in wavelength conversion). Also, considering that the thickness of the first transparent inorganic layer is reduced to be equal to or more than 3.0 eV and equal to or less than 3.4 eV (approximately 360 nm or more in terms of wavelength) in consideration of reducing the thickness in order to suppress the risk of productivity reduction and crack generation. More preferably, the inorganic compound has a band gap of 420 nm or less.
In this specification, the term “main component” refers to a component having the highest content.

As the inorganic compound having a band gap of 2.8 eV or more and 4.8 eV or less, specifically, ZnO, CeO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , SiC, ZnS, etc. are mentioned. Specific examples of the inorganic compound having a band gap of 3.0 eV or more and 3.7 eV or less include ZnO, CeO ₂ , TiO ₂ , Nb ₂ O ₅ , SiC, ZnS, and the like. Further, specific examples of the inorganic compound having a band gap of 3.0 eV or more and 3.4 eV or less include ZnO and CeO ₂ . In consideration of the above, it is preferable that the first transparent inorganic layer contains at least one of ZnO and CeO ₂ .
In this specification, “ZnO” includes ZnO doped with aluminum (Al) and ZnO doped with other elements.
In this specification, “CeO ₂ ” refers to Gadolinium (Gd) -doped CeO ₂ (sometimes collectively referred to as CeGdO ₂ ) (such as Ce _0.9 Gd _0.1 O ₂ ) or samarium (Sm). It has been CeO _2, and is intended to include CeO ₂ doped with other elements.
These inorganic compounds may be used alone in the first transparent inorganic layer, or two or more of them may be used in the first transparent inorganic layer.

  The first transparent inorganic layer preferably has a thickness of 70 nm or more, and more preferably 400 nm or less. When the thickness of the first transparent inorganic layer is 70 nm or more, sufficiently high ultraviolet absorption characteristics can be obtained. When the thickness is 400 nm or less, the risk of lowering productivity and generating cracks can be suppressed. it can. From the same viewpoint, the thickness of the first transparent inorganic layer is more preferably 100 nm or more, and further preferably 300 nm or less.

<Second transparent inorganic layer>
Further, as shown in FIG. 4, the optical body 60 according to the present embodiment preferably includes a second transparent inorganic layer 65 on the first transparent inorganic layer 64 in addition to the first transparent inorganic layer 64. . By providing the second transparent inorganic layer, it is possible to prevent adhesion of dirt to the first transparent inorganic layer due to rain or the like. This second transparent inorganic layer has transparency, may be water repellent or hydrophilic, and can be formed by, for example, a sputtering method or a CVD method.

The main component of the second transparent inorganic layer preferably has a bandgap larger than the bandgap of the main component of the first transparent inorganic layer, and more specifically, the bandgap of the main component of the first transparent inorganic layer. Is also preferably an inorganic compound having a band gap larger than 4.0 eV. When the bandgap of the main component of the second transparent inorganic layer is larger than the bandgap of the main component of the first transparent inorganic layer, preferably 4.0 eV or more, the antifouling property of the first transparent inorganic layer is improved. In addition, the antiglare property of the obtained optical body can be improved.
Specifically, as a preferable main component of the second transparent inorganic layer, an inorganic compound such as SiO ₂ , SiN, SiON, and MgF ₂ is given. In other words, the second transparent inorganic layer preferably contains at least one of SiO ₂ , SiN, SiON and MgF ₂ . Further, the second transparent inorganic layer more preferably contains at least SiO ₂ .
These inorganic compounds may be used alone for the second transparent inorganic layer, or two or more of them may be used for the second transparent inorganic layer.

  The thickness of the second transparent inorganic layer is preferably 20 nm or more, and more preferably 200 nm or less. When the thickness of the second transparent inorganic layer is 20 nm or more and 200 nm or less, the reflectance can be sufficiently reduced, and the antiglare property can be more effectively improved. From the same viewpoint, the thickness of the second transparent inorganic layer is more preferably 40 nm or more, and further preferably 100 nm or less.

<Third transparent inorganic layer>
Further, as shown in FIG. 5, the optical body according to the present embodiment has a third transparent inorganic layer 66 on the second transparent inorganic layer 65 in addition to the first transparent inorganic layer 64 and the second transparent inorganic layer 65. It is preferable to further include By providing the third transparent inorganic layer, it is possible to suppress deterioration of the first transparent inorganic layer and the second transparent inorganic layer due to chemicals. This third transparent inorganic layer has transparency, may be water repellent or hydrophilic, and can be formed by, for example, a sputtering method or a CVD method.

The third transparent inorganic layer can contain, as a main component, at least one of SiO ₂ , SiN, SiON and MgF ₂ . Further, the third transparent inorganic layer preferably further contains ZrO ₂ , Nb ₂ O ₅ , and SnO ₂ as additional components. The proportion of the additional component in the third transparent inorganic layer is preferably from 6% by mass to 50% by mass. When the proportion of the additional component is 6% by mass or more, a sufficient effect of improving chemical resistance can be obtained, and when it is 50% by mass or less, the refractive index with the second transparent inorganic layer can be improved. The difference can be kept at a proper level, and the difficulty of optical design can be avoided. From the same viewpoint, the ratio of the additional component in the third transparent inorganic layer is more preferably 13% by mass or more, further preferably 20% by mass or more, and 30% by mass or less. Is more preferred. The additional components may be used alone or in a combination of two or more.

  The third transparent inorganic layer preferably has a thickness of 20 nm or more. When the thickness of the third transparent inorganic layer is 20 nm or more, sufficiently high chemical resistance can be obtained. In addition, the third transparent inorganic layer preferably has a thickness of 200 nm or less. When the thickness of the third transparent inorganic layer is 200 nm or less, it is possible to suppress a decrease in productivity and a risk of occurrence of cracks. From the same viewpoint, the thickness of the third transparent inorganic layer is more preferably 100 nm or less.

<Antifouling coat layer>
The optical body according to the present embodiment preferably includes an antifouling coat layer on the outermost surface of the fine uneven layer on the side of the fine uneven surface. Specifically, the optical body according to the present embodiment preferably includes an antifouling coat layer on the fine uneven layer, on the second transparent inorganic layer, or on the third transparent inorganic layer. By providing an antifouling coating layer, it is possible to reduce the adherence of dirt to the optical body, and to easily remove the adhered dirt, so that the optical body can exhibit its intended performance for a longer period of time. Can be.
The antifouling coat layer is preferably provided on the second or third transparent inorganic layer mainly composed of SiO ₂ from the viewpoint of high adhesiveness.

  The main component of the antifouling coat layer may be water repellent or hydrophilic, and may be oil repellent or lipophilic. However, from the viewpoint of more effectively improving the antifouling property, the main component of the antifouling coat layer is preferably water-repellent and oil-repellent. Specifically speaking, regarding the water repellency, the antifouling coat layer preferably has a pure water contact angle of 110 ° or more, and more preferably 115 ° or more. As a material having these properties, the main component of the antifouling coat layer is preferably perfluoropolyether.

  The antifouling coat layer preferably has a thickness of 5 nm or more, and more preferably 20 nm or less, for example, 10 nm. When the thickness of the antifouling coat layer is 5 nm or more, the antifouling property of the optical body can be sufficiently enhanced, and when the thickness is 20 nm or less, burying of the uneven structure of the fine uneven layer can be avoided. it can.

<Other layers>
The optical body according to the present embodiment is not particularly limited, and may include other layers other than the above-described layers.
For example, the optical body according to the present embodiment may be provided with an adhesion layer between the above-mentioned fine uneven layer and the first transparent inorganic layer in order to firmly adhere them. As the adhesion layer, for example, an SiO _x layer can be mentioned, and the thickness can be, for example, 2 nm or more and 10 nm or less. This adhesion layer can be formed by, for example, a sputtering method or a CVD method.

In addition, the optical body according to the present embodiment preferably includes an adhesive layer that absorbs visible light on the surface of the fine uneven layer opposite to the fine uneven surface. By providing an adhesive layer that absorbs visible light on the surface opposite to the fine uneven surface, as shown in FIG. 6, a window material 80 in which a glass substrate 81 is laminated on the surface of the optical body provided with the adhesive layer 84 In the above, visible light that passes through the (optional first transparent inorganic layer 64 and) the fine uneven layer 63 and enters the adhesive layer 84, and the (optional first transparent inorganic layer 64) and the fine uneven layer 63 and the adhesive layer After transmitting through the glass substrate 81, the visible light and the like reflected on the glass substrate 81 and incident on the adhesive layer 84 are efficiently absorbed to reduce the visible light transmittance, and the antiglare property is further improved while maintaining high viewability. can do. In addition, by using adhesive layers having different visible light absorptivity, there is an advantage that a product lineup having different gloss levels can be easily prepared.
The adhesive layer that absorbs visible light can be prepared, for example, by using a material having an adhesive property and a coloring agent such as a dye or a pigment that absorbs visible light dispersed in an arbitrary ratio. .
On the other hand, for example, when the proportion of the dye or pigment that absorbs visible light is large, the adhesive strength is reduced, or when there is a problem such as the durability is deteriorated, the coloring agent such as the dye or the pigment is contained. A substrate that absorbs visible light or an inorganic film that absorbs visible light such as DLC may be laminated on the fine uneven layer.

<Characteristics of optical body>
The optical body according to the present embodiment preferably has a glossiness at a measurement angle of 20 ° of 40 or less. When the gloss at a measurement angle of 20 ° is 40 or less, the antiglare property of the optical body can be made sufficiently high. From the same viewpoint, the gloss of the optical body at a measurement angle of 20 ° is more preferably 30 or less, and further preferably 20 or less.
The glossiness of the optical body at a measurement angle of 20 ° can be measured by the method used in the examples.

In the optical body according to the present embodiment, it is preferable that the transmitted image clarity at an optical comb width of 2 mm is 50% or more. When the clearness of the transmitted image at the optical comb width of 2 mm is 50% or more, the viewability of the optical body can be made sufficiently high. From the same viewpoint, the transmitted image definition at an optical comb width of 2 mm of the optical body is more preferably 70% or more, and further preferably 80% or more.
Note that the transmitted image definition at an optical comb width of 2 mm of the optical body can be measured by the method used in Examples.

The optical body according to the present embodiment preferably has a total haze of 15% or more and 60% or less. When the total haze is 15% or more, the antiglare property can be effectively improved, and when it is 60% or less, the viewability can be effectively improved. From the same viewpoint, the total haze of the optical body is more preferably 50% or less.
The optical body according to the present embodiment preferably has an internal haze of 4% or less. When the internal haze is 4% or less, the viewability can be further improved. From the same viewpoint, the internal haze of the optical body is more preferably 2% or less.
The total haze and the internal haze of the optical body can be measured by the method used in the examples.

The optical body according to the present embodiment preferably has a transmittance of light having a wavelength of 320 nm of 10% or less, more preferably 6% or less, and further preferably 3% or less. When the transmittance of light having a wavelength of 320 nm of the optical body is 10% or less, deterioration such as yellowing of the base material due to ultraviolet rays can be effectively suppressed, and adhesion durability between the base material and the resin layer can be improved. Can be improved.
In addition, the transmittance | permeability of the light of the wavelength of 320 nm of an optical body can be measured using JASCO Corporation "V-560", for example.

(Window material)
A window material according to an embodiment of the present invention (hereinafter, may be referred to as “window material according to the present embodiment”) includes a glass substrate and the above-described optical body. Specifically, as shown in FIG. 7, the window material 80 according to the present embodiment is configured such that the above-described optical body 60 and the glass 81 so as to face each other. As described above, the window material according to the present embodiment includes at least the above-described optical body, and is excellent in both anti-glare properties and viewability. Therefore, window glasses for buildings such as high-rise buildings and houses, window glasses for vehicles, and the like. Can be suitably used.
In addition, the window material according to the present embodiment may include the above-described optical body on only one side of the glass substrate, or may include the optical body on both sides.

  Further, based on the same concept as the above-described optical body, in the window material according to the present embodiment, the glossiness at a measurement angle of 20 °, the clearness of a transmitted image at an optical comb width of 2 mm, the total haze, the internal haze, and the light of a wavelength of 320 nm. The preferable range of the transmittance and the reason why the range is preferable are the same as those described above for the optical body.

  The window material according to the present embodiment may be a double glazing. In general, double glazing is inferior in antiglare properties to single glazing, but the window material according to the present embodiment is provided with the above-described optical body. Can be brought.

Here, as shown in FIG. 8, the multi-layer glass is generally formed by laminating a plurality of glass substrates (82, 83) with a spacer 85 interposed therebetween so that a space is formed between the glass substrates. Refers to glass having a certain structure.
As shown in FIG. 8A, the window material 80 according to the present embodiment, which is a multi-layer glass, is provided on the outdoor side of a glass substrate 82 which is an outdoor side when installed on a building or the like as a window glass. The optical body 60 may be provided only on the surface, and as shown in FIGS. 8B to 8D, the optical body 60 is provided on the outdoor side surface of the glass substrate 82 which is the outdoor side. At the same time, the optical body 60 may be provided on one side and / or both sides of the glass substrate 83 on the indoor side, and further, as shown in FIGS. 8 (e) to 8 (h), the glass on the outdoor side. The optical body may be provided on both sides of the substrate 82 and, optionally, on one and / or both sides of the glass substrate 83 on the indoor side.

  Further, when the window material according to the present embodiment is a double-glazed glass, and the optical body is provided on the outdoor surface of the glass substrate that becomes the outdoor when installed in a building or the like as the window glass. It is particularly preferable to provide an adhesive layer that absorbs visible light on the surface (more specifically, between the optical member and the glass substrate) on the side opposite to the fine uneven surface of the optical member. By providing such an adhesive layer that absorbs visible light, visible light penetrating the optical body and entering the adhesive layer, after passing through the optical body and the adhesive layer, the indoor surface of the outdoor glass substrate. The visible light that is reflected and enters the adhesive layer, and passes through the optical body, the adhesive layer and the outdoor glass substrate, is reflected by the indoor glass substrate, passes through the outdoor glass substrate, and forms the adhesive layer. It is possible to efficiently absorb incident visible light and the like to reduce the visible light transmittance, and to solve the problem of antiglare property that the double-glazed glass can frequently face while maintaining high viewability.

  Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Examples 1 to 5, Comparative Examples 1 and 2)
A resin layer having a fine uneven structure is formed on a PET base material (manufactured by Toyobo Co., Ltd., “A4300”, thickness 75 μm) by a shape transfer method using a composition containing an acrylic ultraviolet curable resin. Then, an optical body was obtained. In forming the fine concavo-convex layer at this time, each parameter (Ra: arithmetic average roughness (μm), RSm: average length of roughness curve element (μm), specific surface area) relating to the surface of the optical body is shown in Table 1. The conditions of the shape transfer method were appropriately adjusted such as changing the surface shape of the master so as to obtain the indicated value. Next, an adhesive layer (substrate-less double-sided adhesive tape, “MHM-FW25” manufactured by Niei Chemical Industries, Ltd., thickness 25 μm) is laminated on the surface of the PET substrate opposite to the surface on which the resin layer is formed. And a 3 mm thick blue plate glass (float plate glass specified in JIS R3202).

  With respect to the optical body (window material) to which the soda lime glass thus obtained is bonded, measurement of the arithmetic average roughness Ra, the average length RSm of the roughness curve element and the specific surface area, and the haze are performed by the following methods. Was measured, and the antiglare property and the viewability were evaluated.

<Measurement of arithmetic average roughness Ra, average length RSm of roughness curve element, specific surface area>
Using “NewView 7300” manufactured by Canon Inc., in accordance with ISO25178 and JIS B0601, the arithmetic average roughness Ra of the fine uneven surface, the average length RSm of the roughness curve element, the specific surface area (the area of the area in the unit area) (Ratio of surface area to). Specific conditions include software: MtroPro 8.3.5, Acquisition Mode: Scan, Scan Type: Bipolar, zoom lens: 2x, objective lens: 200x, mode: High 2G, surface correction: Cylinder, Camera Mode: 640 × 480 210 Hz. The measurement was performed in a rectangular area of 35.3 μm × 26.5 μm arbitrarily selected from the fine uneven surface. Table 1 shows the results.

<Haze measurement>
Using “NDH 7000SP” manufactured by Nippon Denshoku Industries Co., Ltd., the total haze and the internal haze were measured in accordance with JIS K7136. Table 1 shows the results.

<Evaluation of anti-glare property>
The optical body (window material) to which the blue plate glass is bonded is placed on a flat surface with the blue plate glass facing down, and is compliant with JIS Z8741 using a portable gloss meter (“Micro Gloss” manufactured by BYK Gardner). Then, the gloss G at a measurement angle of 20 ° was measured. In addition, a non-reflection plate (Carbon Feather 188X1B, manufactured by Kimoto Co., Ltd.) was laid on the plane on which the optical body was placed so that the influence of the underlayer was minimized. From the value of the gloss G, the antiglare property was evaluated according to the following criteria. Table 1 shows the results.
Gloss G is 30 or less ...
Gloss G is more than 30 and 40 or less ... 〇 Gloss G is more than 40 ... ×

<Evaluation of viewability>
Using a touch panel type image clarity measuring device (“ICM-1T” manufactured by Suga Test Instruments Co., Ltd.), transmission of an optical body (window material) to which a soda lime glass is bonded in an optical comb width of 2 mm in accordance with JIS K7374. Image sharpness T (%) was measured. From the value of the transmitted image definition T, the viewability was evaluated according to the following criteria. Table 1 shows the results.
Transmission image sharpness T is 70% or more.
Transmitted image sharpness T is 50% or more and less than 70% ... 〇 Transmitted image sharpness T is less than 50% ... ×

  From Table 1, in Examples 1 to 5, Ra is 0.2 μm or less, and since at least one of RSm and specific surface area is within a predetermined range, it is possible to achieve both antiglare property and viewability. You can see that it is done.

  ADVANTAGE OF THE INVENTION According to this invention, the optical body which is excellent in anti-glare property and viewability, and the window material which is excellent in anti-glare property and viewability can be provided.

REFERENCE SIGNS LIST 1 shape transfer device 2 master 23 fine uneven structure 51 substrate supply roll 52 take-up roll 53, 54 guide roll 55 nip roll 56 peeling roll 57 coating device 58 light source 60 optical body 61 base 62 resin layer 63 fine uneven layer 64 first Transparent inorganic layer 65 Second transparent inorganic layer 66 Third transparent inorganic layer 80 Window material 81, 82, 83 Glass substrate 84 Adhesive layer 85 Spacer

Claims (6)

An optical body having a fine uneven layer,
In a rectangular area of 35.3 μm × 26.5 μm on the fine uneven surface,
Arithmetic mean roughness Ra is 0.2 μm or less; and
The average length RSm of the roughness curve element is 10 μm or less, or the ratio of the surface area to the area of the rectangle is 1.04 or more and 1.5 or less;
An optical body, characterized in that: Further comprising a first transparent inorganic layer and a second transparent inorganic layer,
The optical body according to claim 1, wherein the first transparent inorganic layer is disposed on a fine uneven surface of the fine uneven layer, and the second transparent inorganic layer is arranged on the first transparent inorganic layer. The first transparent inorganic layer contains at least one of ZnO and CeO ₂ ,
It said second transparent inorganic layer, SiO _2, SiN, contains at least one of SiON and MgF _2, the optical body of claim 2.   The total haze is 15% or more and 60% or less, the internal haze is 4% or less, the gloss at a measurement angle of 20 ° is 40 or less, and the transmitted image clarity at an optical comb width of 2 mm is 50% or more. The optical body according to any one of claims 1 to 3.   The optical body according to claim 2, further comprising a third transparent inorganic layer on the second transparent inorganic layer.   A window material comprising: a glass substrate; and the optical body according to claim 1.

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