Patent Application
20120300306
The present invention relates to an optical body, a method of manufacturing the same, a window member, a fitting, and a solar shading device. In particular, the invention relates to an optical body that can block sunlight.
Recently, a film or a pane for a window to block sunlight is used from the viewpoint of reducing air conditioning load. Especially, a film or a pane that blocks visible light rays as well as infrared light at the same time is used because over the half of solar energy is visible light rays. Moreover, it is important to partially block the visible light rays in view of the purpose of reducing glare caused by late afternoon sunlight.
A transflective layer made of a metal obtained through film deposition is known as such a film or a pane (for example, see Patent Documents 1 to 3). However, since a transflective layer is deposited on a flat plate in these films or panes, visible light rays are reflected therefrom, thereby forming a mirror shape. Therefore, a problem of glare or reflection arises.
Accordingly, the present invention is intended to provide an optical body, a method of manufacturing the same, a window member, a fitting, and a solar shading device, each capable of blocking sunlight including visible light rays as well as suppressing glare and reflection.
In order to address the above-mentioned problems, a first invention provides
an optical body including:
a first optical layer that has a concave-convex surface,
a transflective layer formed on the concave-convex surface, and
a second optical layer formed to enclose concave and convex portions on the concave-convex surface on which the transflective layer is formed, in which
the transflective layer directionally reflects a portion of light, incident on an incidence surface at an incidence angle (θ, φ), in a direction other than a direction of regular reflection (−θ, φ+180°).
(Wherein, θ: an angle formed by a perpendicular line perpendicular to the incidence surface, and incident light incident on the incidence surface or reflected light exiting from the incidence surface, an angle formed by a specific linear line l2 in the incidence surface and a component of the incident light or the reflected light projected on the incidence surface, and the specific linear line l2 in the incidence surface: an axis where an intensity of reflection in a direction φ becomes maximum when the incidence angle (θ, φ) is fixed and the transflective layer is rotated about the perpendicular line l1, serving as an axis, perpendicular to the incidence surface)
A second invention includes steps of:
forming a first optical layer that has a concave-convex surface;
forming a transflective layer on the concave-convex surface of the first optical layer, and
forming a second optical layer on the transflective layer to enclose concave and convex portions on the concave-convex surface on which the transflective layer is formed, in which the transflective layer directionally reflects a portion of light, incident on an incidence surface at an incidence angle (θ, φ), in a direction other than a direction of regular reflection (−θ, φ+180°).
(Where, θ: an angle formed by a perpendicular line l1 perpendicular to the incidence surface, and incident light incident on the incidence surface or reflected light exiting from the incidence surface, φ: an angle formed by a specific linear line l2 in the incidence surface and a component of the incident light or the reflected light projected on the incidence surface, and the specific linear line l2 in the incidence surface: an axis where an intensity of reflection in a direction φ becomes maximum when the incidence angle (θ, φ) is fixed and the transflective layer is rotated about the perpendicular line l1, serving as an axis, perpendicular to the incidence surface).
In the present invention, since the transflective layer is formed on the concave-convex surface of the first optical layer, sunlight including visible light rays can be blocked as well as glare or reflection can be suppressed. Moreover, since the concave-convex surface of the first optical layer on which the transflective layer is formed is enclosed by the second optical layer, a transmission image becomes clearly visible.
As described above, according to the present invention, sunlight including visible light rays can be blocked as well as glare and reflection can be suppressed.
Embodiments of the present invention are described in the following order with reference to the drawings.
1. First embodiment (example in which structures are one-dimensionally arrayed)
2. Second embodiment (example in which structures are two-dimensionally arrayed)
3. Third embodiment (example of a louver-type transflective layer)
4. Fourth embodiment (example in which a light scattering body is disposed in an optical film)
5. Fifth embodiment (example in which a self-cleaning layer is provided)
6. Sixth embodiment (example in which an optical film is applied to a blind device)
7. Seventh embodiment (example in which an optical film is applied to a roll screen device)
8. Eighth embodiment (example in which an optical film is applied to a fitting)
The optical film 1 may further include a first base 4a in the exit surface S2 of the optical layer 2 if necessary. Moreover, the optical film 1 may further include a second base 5a in the incidence surface S1 of the optical layer 2 if necessary. When the first base 4a and/or the second base 5a are included in the optical film 1 in this way, the optical film 1 preferably satisfies optical properties such as transparency and transmission color to be described below in a state in which the optical film 1 is equipped with the first base 4a and/or the second base 5a.
The optical film 1 may further include an affixing layer 6 if necessary. Among the incidence surface S1 and the exit surface S2 of the optical film 1, the affixing layer 6 is formed on the surface which is to be affixed to the window member 10. The optical film 1 is affixed to the indoor side or the outdoor side of the window member 10 serving as an adherend via the affixing layer 6. For example, the affixing layer 6 can use an adhesion layer (for example, UV-curable resin or two-liquid mixed resin) of which a main component is adhesion bond, or an adhesive layer (for example, PSA: Pressure Sensitive Adhesive) of which a main component is an adhesive. When the affixing layer 6 is the adhesive layer, a release layer 7 is preferably included on the affixing layer 6. When adopting this construction, the optical film 1 could be easily affixed to the adherend, such as the window member 10, via the affixing layer 6 only by a simple operation of peeling off the release layer 7.
The optical film 1 may further include a primer layer (not illustrated) between the second base 5a, and the affixing layer 6 and/or the second optical layer 5 from the viewpoint of improving bondability between the second base 5a, and the bonding layer 6 and/or the second optical layer 5. Moreover, from the viewpoint of improving the bondability of similar portions, a well-known physical pretreatment is preferably performed instead of using the primer layer or is performed in combination with use of the primer layer. Examples of the well-known physical pretreatment include plasma treatment, corona treatment, etc.
The optical film 1 may further include a barrier layer (not illustrated) on the incidence surface S1 or the exit surface S2 which is to be affixed to the adherend, such as the window member 10, or between such a surface and the transflective layer 3. The addition of the barrier layer has an effect of reducing diffusion of moisture from the incidence surface S1 or the exit surface S2 toward the transflective layer 3, and an effect of suppressing degradation of a metal contained in the transflective layer 3. Accordingly, the durability of the optical film 1 can be improved.
The optical film 1 may further include a hard-coat layer 8 from the viewpoint of imparting scratch resistance, etc. to the surface. The hard-coat layer 8 is preferably formed on one of the incidence surface S1 or the exit surface S2 of the optical film 1, that is, on the surface being opposite to the surface to be affixed to the adherend such as the window member 10. The optical film 1 may further include a layer that has a water repellent or hydrophilic property on the incidence surface S1 from the viewpoint of imparting an antifouling property to the incidence surface S1. The layer that has such functions may be directly disposed on the optical layer 2 or on any one of various functional layers such as the hard-coat layer 8 for example.
From the viewpoint of enabling the optical film 1 to be easily affixed to the adherend such as the window member 10, the optical film 1 preferably has flexibility. Here, the term “film” has a meaning including sheet. That is, an optical sheet can be interpreted as the optical film 1.
The optical film 1 has transparency. The term “transparency” preferably implies that transmission image visibility is in the following range. A difference in refractive index between the first optical layer 4 and the second optical layer 5 is preferably 0.010 or less, more preferably 0.008 or less, and even more preferably 0.005 or less. The transmission image tends to appear blurred when the refractive index difference exceeds 0.010. When it is within a range of from over 0.008 to 0.010 or under, there is no problem in daily living though the transmission image visibility varies depending on brightness on the outside. When it is within a range of from over 0.005 to 0.008 or under, the outside scenery is clearly visible though a diffraction pattern of an object as very bright as a light source is concerning. If it is 0.005 or less, the diffraction pattern is scarcely concerning. Among the first optical layer 4 and the second optical layer 5, an optical layer that is to be affixed to the window member 10 or the like may contain an adhesive as a main component. By adopting such a construction, the optical film 1 can be affixed to the window member 10 or the like by the first optical layer 4 or the second optical layer 5 containing an adhesive as a main component. Moreover, by adopting such a construction, the difference in the refractive index of the adhesive is preferably within the above-mentioned range.
The first optical layer 4 and the second optical layer 5 are preferably the same in optical properties such as a refractive index. More specifically, the first optical layer 4 and the second optical layer 5 are preferably made of the same material having transparency in the visible region, for example, they are made of the same resin material. Since the first optical layer 4 and the second optical layer 5 are made of the same material, the refractive indexes of both are equal, which increases the transparency in the visible light. However, even though starting materials thereof are the same, special care is necessary because the refractive index of a finished layer might vary depending on curing conditions or the like in a coating process. On the other hand, when the first optical layer 4 and the second optical layer 5 are made of different materials, they may have different refractive indexes. Therefore, light is refracted in the transflective layer 3 serving as a border, and the transmission image tends to appear blurred. Especially when an object located near a point light source such as a distant lamp is viewed, the diffraction pattern tends to be remarkably conspicuous. Moreover, the first optical layer 4 and the second optical layer 5 may be made of the same material that has transparency in the visible region, and the second optical layer 5 may contain an additive such as a phosphate compound or the like. Alternatively, the additive may be mixed in the first optical layer 4 and/or the second optical layer 5 to adjust the value of the refractive index.
The first optical layer 4 and the second optical layer 5 preferably have transparency in the visible region. Here, the term “transparency” has two kinds of definitions: there is no absorption of light; and there is no scattering of light. Generally, when saying a thing has transparency, it refers to the former definition. However, both are preferably required for the optical film 1 according to the first embodiment. Retroreflectors which are currently being used are intended to enable people to recognize reflected light of a display color, that is, aim at helping people recognize nighttime worker's clothes or roadway signs. Accordingly, even if it has a scattering property for example, when it is in tight contact with an underlying reflector, the reflected light is visible. For example, the principle is the same as the case that even if an anti-glare treatment to impart a scattering property is performed on the front surface of an image display unit for the purpose of imparting an anti-glare property, the image is visible. However, the optical film 1 according to the first embodiment has a feature such that it transmits light other than a specific wavelength which is directionally reflected. It is preferable that the optical film 1 has nearly no scattering property in order to observe transmitted light in a state in which it is attached to a transmissive body that transmits mainly such a transmission wavelength. However, the second optical layer 5 may be intentionally given the scattering property depending on its usage.
The optical film 1 is used, for example, in such a way that it is affixed, via an adhesive, to a rigid body, such as the window member 10 that has transparency mainly with respect to the light that has passed through the optical film 1. Examples of the window member 10 include a window member for a building such as a skyscraper or a house, a window member for a vehicle, etc. When the optical film 1 is applied to the window member for a building, it is particularly preferable that the optical film 1 is applied to the window member 10 that is disposed to face in a certain direction within the range, in particular, from east to south and further to west (e.g., within a range of from southeast to southwest). When it is applied to the window member 10 disposed in such a position, heat rays can be reflected more effectively. The optical film 1 can be used not only for a pane of a monolayer but also for a special glass such as double-glazed glass. Moreover, the window member 10 may not be limited to ones made of glass, but may also be applied to ones made of a transparent polymeric material. The optical layer 2 preferably has transparency in the visible region. As having the transparency, the visible light is transmitted when the optical film 1 is affixed to the window member 10, such as a pane, so that natural lighting by sunshine can be secured. Moreover, it can be affixed not only to the inside surface of the glass but also to the outside surface to be used.
Moreover, the optical film 1 can be used in combination with an additional heat-ray cutting film. For example, a light absorption coating may be disposed at the interface between air and the optical film 1 (i.e., on the outermost surface of the optical film 1). Moreover, the optical film 1 can be used in combination with a hard-coat layer, an ultraviolet lay cutting layer, a surface anti-reflection layer, etc. When these functional layers are used in a combined manner, these functional layers are preferably disposed at the interface between the optical film 1 and air. However, when a UV-cutting layer is used, it needs to be located nearer the sun than the optical film 1. Therefore, the UV-cutting layer is desirably disposed between the surface of the pane and the optical film 1 especially when it is used as a lining for an inside surface of the pane. In this case, an UV absorbing agent is kneaded in a bonding layer between the surface of the pane and the optical film 1.
Depending on the usage of the optical film 1, the optical film 1 may be colored to have a visually attractive design. When the visually attractive design is given, it is preferable that at least one of the first optical layer 4 and the second optical layer 5 is constructed to primarily absorb light in a particular wavelength band within the visible region to such an extent not reducing transparency thereof.
Light that is directionally reflected is preferably the light within a wavelength bandwidth of 400 nm or longer and 2100 nm or shorter. The reason for this is that 90% or more of the solar energy is included in this region. However, the light of the wavelength bandwidth of 2100 nm or more may be reflected. A ratio of transmittance for a wavelength of 500 nm with respect to transmittance for a wavelength of 1000 nm is preferably 1.8 or less, more preferably 1.6 or less, and even more preferably 1.4 or less. When it has wavelength selectivity, the visible light passes through it and is then absorbed by the indoor floor, resulting in heat being generated. When the film of the present invention is applied to a window on the west side, there is a problem such as glaring of the setting sun.
Moreover, since it has no wavelength selectivity, the color tone of the film approximates neutral. Preferable ranges of the transmissive color tone for a D65 light source are 0.280≦x≦0.345 and 0.285≦y≦0.370, more preferable ranges are 0.285≦x≦0.340 and 0.290≦y≦0.365, and even more preferable ranges are 0.290≦x≦0.320 and 0.310≦y≦0.340.
In the optical film 1, the direction φo of the directional reflection is preferably within the range of from −90° to 90°. This is because a portion of the light that is incident from the sky can be returned in the direction of the sky when the optical film 1 is affixed to the window member 10. The optical film 1 within this range is useful for a case where there are no high buildings in the surrounding. Preferably, the direction of the directional reflection is in the vicinity of (θ, −φ). The vicinity preferably refers to the range within five degrees from (θ, −φ), more preferably the range within three degrees from (θ, −φ), and even more preferably the range within two degrees from (θ, −φ). It is because when the directional reflection occurs within such a range, a portion of the light that has entered, from the sky, into each building arrayed in a row and having similar heights can be efficiently returned to the sky above the other buildings when the optical film 1 is affixed to the window member 10. For example, in order to achieve such directional reflection, a portion of a spherical surface or a hyperboloid surface, or a three-dimensional structure, such as a triangular pyramid, a square pyramid, and a circular cone is preferably used. The light that is incident in a direction (θ, φ) (−90°<φ<90°) can be reflected in a direction (θo, φo) (0°<θo<90°, −90°<φo<90°) depending on its shape. Or, preferably a cylindrical body that expands in one direction is used. The light that is incident in the direction (θ, φ) (−90°<φ<90°) can be reflected in the direction (θo, −φ) (0°<θo<90°) depending on an inclination angle of the cylindrical body.
Preferably, the incident light is directionally reflected from the optical film 1 in a direction which is in the vicinity of the direction of retroreflection. In other words, the direction of the reflection of the light, which has been incident on the incidence surface S1 at the incidence angle (θ, φ), is preferably in the vicinity of (θ, φ). The reason is that when the optical film 1 is affixed to the window member 10, it can cause a portion of the light incident from the sky to turn back toward the sky. Herein, the term “vicinity” implies that a deviation in the direction of the directional reflection is preferably within 5 degrees, more preferably within 3 degrees, and even more preferably within 2 degrees. By setting the direction of the directional reflection to the above-mentioned range, when the optical film 1 is affixed to the window member 10, the optical film 1 can efficiently cause the light incident from the sky to turn back toward the sky. Moreover, in a case where an infrared-light emitting unit and a light receiving unit like an infrared sensor or an infrared imaging are located adjacent to each other, the direction of retroreflection has to be set aligned with the incident direction. However, when sensing in a specific direction is not necessary as in the embodiments of the present invention, those directions may be set not so exactly aligned with each other.
The value of the transmittance image visibility for a D65 light source is preferably 30 or more, more preferably 50 or more, and even more preferably 70 or more when an optical comb of 0.5 mm is used for measurement. When the value of the transmission image visibility is less than 30, the transmission image tends to appear blurred. When it is 30 or more and less than 50, there is no problem in daily living though depending on brightness on the outside. When it is 50 or more and less than 75, the diffraction pattern is concerning only for an object as very bright as a light source, but the outside scenery is clearly visible. When it is 75 or more, the diffraction pattern is scarcely concerning. A total of the values of the transmittance image visibility measured by using optical combs of 0.125 mm, 0.5 mm, 1.0 mm, and 2.0 mm, respectively is preferably 170 or more, more preferably 230 or more, and even more preferably 350 or more. When the total of the values of the transmission image visibility is less than 170, the transmission image tends to appear blurred. When it is 170 or more and less than 230, there is no problem in daily living though depending on brightness on the outside. When it is 230 or more and less than 350, the diffraction pattern is concerning only for an object as very bright as a light source, but the outside scenery is clearly visible. When it is 350 or more, the diffraction pattern is scarcely concerning. Herein, the values of the transmission image visibility were measured based on JIS K7105 by using ICM-1T manufactured by Suga Test Instruments Co. Ltd.
The incidence surface S1 of the optical film 1, or preferably the incidence surface S1 and the exit surface S2 of the optical film 1 have an extent of smoothness that does not decrease the transmission image visibility. Specifically, an arithmetic mean roughness Ra of the incidence surface S1 and the exit surface S2 is 0.08 μm or less, preferably 0.06 μm or less, and even more preferably 0.04 μm or less. The arithmetic mean roughness Ra is calculated as a roughness parameter by measuring the surface roughness of the incidence surface, and acquiring a roughness curve from a two-dimensional profile curve. The measurement conditions conform to JIS B0601:2001. A measuring instrument and measurement conditions are listed below. Measuring instrument: Fully-automatic microfigure measuring instrument Surf corder ET4000A (Osaka laboratory Ltd.)
λc=0.8 mm
Evaluation length: 4 mm
Cutoff×5
Data sampling interval: 0.5 μm
Hereinafter, the first optical layer 4, the second optical layer 5, and the transflective layer 3 which constitute the optical film 1 will be described in this order.
(First Optical Layer and Second Optical Layer)
The first optical layer 4 is a layer to support and protect the transflective layer 3 for example. For example, the first optical layer 4 is formed of a layer containing a resin as a main component from the viewpoint of imparting flexibility to the optical film 1. Among both principal surfaces of the first optical layer 4, for example, one surface is a smooth surface, and the other is a concave-convex surface (first surface). The transflective layer 3 is formed on the concave-convex surface.
The second optical layer 5 is a layer to protect the transflective layer 3 by enclosing the first surface (concave-convex surface) of the first optical layer 4 on which the transflective layer 3 is formed. For example, the second optical layer 5 is formed of, for example, a layer containing a resin as a main component from the viewpoint of imparting flexibility to the optical film 1. Among both principal surfaces of the second optical layer 5, for example, one surface is a smooth surface, and the other is a concave-convex surface (second surface). The concave-convex surface of the first optical layer 4 and the concave-convex surface of the second optical layer 5 are reversed to each other in a concave-convex relation.
For example, the concave-convex surface of the first optical layer 4 is formed by a plurality of structures 4c which is one-dimensionally arrayed. For example, the concave-convex surface of the second optical layer 5 is formed by a plurality of structures 5c which is one-dimensionally arrayed (See
In the optical film 1, a pitch P of the structures 4c is preferably 5 μm or more and 5 mm or less, more preferably 5 μm or more and less than 250 μm, and even more preferably 20 μm or more and 200 μm or less. When the pitch of the structures 4c is less than 5 μm, it is difficult to process the structures 4c into a desired shape, so it is difficult to obtain desired directional reflection. On the other hand, when the pitch of the structures 4c exceeds 5 mm, a necessary film thickness has to be increased in consideration of the shape of the structures 4c needed to obtain the directional reflection. Therefore, the film loses its flexibility and the film is difficult to be affixed to a rigid body such as the window member 10 or the like. Moreover, when the pitch of structures 11a is set to be less than 250 μm, the flexibility more increases, and roll-to-roll manufacturing is facilitated, resulting in batch type production becoming unnecessary. In order to apply an optical device of the present invention to building materials such as a widow, the optical device needs to be several meters in length. Accordingly, the roll-to-roll manufacturing is more suitable than batch type production. In addition, when the pitch is set to be 20 μm or more and 200 μm or less, the productivity more improves.
The shape of the structures 4c formed on the surface of the first optical layer 4 may not be limited to one kind. The structures 4c of different kinds of shapes can be formed on the surface of the first optical layer 4. When the structures 4c of different kinds of shapes are formed on the surface, a given pattern formed by the structures 4c of different kinds of shapes may be periodically repeated. Moreover, the plural kinds of structures 4c may be formed at random (aperiodically) depending on the desired characteristic.
Examples of the shape of the structure 4c include a prism shape illustrated in
Moreover, as illustrated in
The first optical layer 4 may be mainly made of a resin which exhibits a small decrease in storage elastic modulus at 100° C. and has a small difference between the storage elastic modulus at 25° C. and the storage elastic modulus at 100° C. Specifically, it preferably contains a resin having a storage modulus of 3×109 Pa or less at 25° C. and a storage modulus of 3×107 Pa or more at 100° C. The first optical layer 4 is preferably made of one kind of resin, or may contain two or more kinds of resins. Moreover, additives may be further mixed if necessary.
When it contains a resin, as a main component, which exhibits a small decrease in the storage elastic modulus at 100° C. and has a small difference between the storage elastic modulus at 25° C. and the storage elastic modulus at 100° C., even when a process using heat or a process using a combination of heat and pressure is to be performed after the concave-convex surface (first surface) of the first optical layer 4 is formed, the designed interface shape can be maintained substantially as it is. On the other hand, when it contains a resin, as a main component, which exhibits a large decrease in the storage elastic modulus at 100° C. and has a large difference between the storage elastic modulus at 25° C. and the storage elastic modulus at 100° C., the designed interface shape is deformed or the optical film 1 is likely to curl.
Herein, examples of the process using heat include not only a process which directly applies heat to the optical film 1 or to constituent members thereof, such as an annealing process, but also a process which indirectly applies heat by an locally increased temperature of the surface of a deposited film during deposition of a thin film or during curing of a resin composition, and a process which indirectly applies heat to the optical film by an increased temperature of a mold attributable to energy-ray irradiation thereto. Moreover, the effect achieved by limiting the value of the storage elastic modulus to the above mentioned range is not especially limited by the kind of the resin, and can be obtained with any of a thermoplastic resin, a thermosetting resin, and an energy-ray irradiation resin.
The storage elastic modulus of the first optical layer 4 can be confirmed, for example, in the following way. When the surface of the first optical layer 4 has been exposed, the storage elastic modulus of the exposed surface can be confirmed by measurement using a micro-hardness tester. Moreover, when the first base 4a or the like is formed on the surface of the first optical layer 4, after the first base 4a or the like is peeled off so that the surface of the first optical layer 4 is exposed, the storage elastic modulus of the exposed surface is measured with the micro-hardness tester.
Regarding a method of suppressing the decrease in the elastic modulus at a high temperature, in the case of using the thermoplastic resin, a method of adjusting the length and kind of a side chain can be used. Further, in the cases of using the thermosetting resin and the energy-ray irradiation resin, a method of adjusting the number of cross-linking points and the molecular structure of a cross-linking material can be used. However, it is preferable that the characteristic required as the resin material is not impaired by the structural change. For example, for some kinds of cross-linking agents, their elastic modulus increases, they become fragile, or they shrink greatly at a temperature in the vicinity of the room temperature so that the film is likely to curve or curl. Accordingly, it is preferable that the kind of the cross-linking agent is appropriately selected according to the desired characteristic.
When the first optical layer 4 contains a crystalline polymer material as a main component, it is preferable that the first optical layer 4 contains, as the main component, a resin that has a glass transition point higher than the highest temperature in the manufacturing process, and exhibits a small decrease in the storage elastic modulus at the highest temperature in the manufacturing process. If such a resin is used that has a glass transition point within the range of from the room temperature of 25° C. or higher to the highest temperature in the manufacturing process or lower, and exhibits a large decrease in the storage elastic modulus at the highest temperature in the manufacturing process, the designed ideal interface shape is difficult to be maintained through the manufacturing process.
When the first optical layer 4 contains a non-crystalline polymer material as a main component, it is preferable that the first optical layer 4 contains, as a main component, a resin that has a melting point higher than the highest temperature in the manufacturing process, and exhibits a small decrease in the storage elastic modulus at the highest temperature in the manufacturing process. If such a resin is used that has a melting point within the range of from the room temperature of 25° C. or higher to the highest temperature in the manufacturing process or lower and exhibits a large decrease in the storage elastic modulus at the highest temperature in the manufacturing process, the designed ideal interface shape is difficult to be maintained through the manufacturing process.
Herein, the highest temperature in the manufacturing process means the highest temperature of the concave-convex surface (first surface) of the first optical layer 4 in the manufacturing process. It is preferable that the second optical layer 5 satisfies a numerical value range of the storage elastic modulus mentioned above and the temperature range of the glass transition point.
That is, at least one of the first optical layer 4 and the second optical layer 5 preferably contains a resin whose elastic storage modulus is 3×109 Pa or less at 25° C. The reason is that the manufacturing of the optical film 1 by the roll-to-roll process is possible because the flexibility can be imparted to the optical film 1 at the room temperature of 25° C.
For example, the first base 4a and the second base 5a have transparency. Regarding the shape of the base, a film shape is preferably adopted from the viewpoint of imparting the flexibility to the optical film 1, but the shape may not be limited thereto. As the material of the first base 4a and the second base 5a, for example, a well-known polymer material can be used. Examples of the well-known polymer material include triacetyl cellulose (TAC), polyester (TPEE), polyethylene terephthalate (PET), polyimide (PI), polyamide (PA), aramid, polyethylene (PE), acrylic resin, polyether sulfone, polysulfone, polypropylene (PP), diacetyl cellulose, polyvinyl chloride, acryl resin (PMMA), polycarbonate (PC), epoxy resin, urea resin, urethane resin, and melamine resin, etc. However, it is not particularly limited to these materials. The thickness of the first base 4a and the second base 5a is not especially limited, but it is preferably within the range of 38 μm to 100 μm from the viewpoint of productivity. The first base 4a and the second base 5a preferably transmit an energy ray. This reason is that, with respect to the energy-ray curable resin interposed between the first base 4a and the transflective layer 3 or between the second base 5a and the transflective layer 3, as described below, the energy-ray curable resin can be cured by irradiated with the energy ray from the side where the first base 4a or the second base 5a is disposed.
The first optical layer 4 and the second optical layer have transparency for example. The first optical layer 4 and the second optical layer 5 are obtained, for example, by curing a resin composition. As the resin composition, an energy-ray curable resin which is cured by light or an electronic beam, or thermosetting resin which is cured by heat is preferably used from the viewpoint of the ease of manufacturing. As the energy-ray curable resin, a photoresist resin composition which is cured by light is preferably used, but an ultraviolet-ray curable resin composition which is cured by an ultraviolet ray is most preferably used. The resin composition may further contain a compound having phosphoric acid, a compound having succinic acid, and a compound having butyrolactone from the viewpoint of enhancing the adhesion between the first optical layer 4 and the second optical layer 5, or between the first optical layer 4 and the transflective layer 3. As the compound having phosphoric acid, (meth)acrylate having phosphoric acid is used for example, and preferably (meth)acrylic monomer or oligomer that has phosphoric acid in a functional group can be used. As the compound having succinic acid, (meth)acrylate having succinic acid is used for example, and preferably (meta) acrylic monomer or oligomer which has succinic acid in a functional group can be used. As the compound having butyrolactone, (meth)acrylate having butyrolactone can be used for example, and preferably (meth)acrylic monomer or oligomer that has butyrolactone in a functional group can be used.
The ultraviolet-ray curable resin composition contains, for example, (meth)acrylate. Furthermore, the ultraviolet-ray curable resin composition may further contain a light stabilizer, a flame retardant, a leveling agent, and an anti-oxidant, etc. if necessary.
Preferably, a monomer and/or oligomer having two or more of (meth)acryloyl groups is used as the acrylate. Examples of such a monomer and/or oligomer include urethane(meth)acrylate, epoxy(meth)acrylate, polyester(meth)acrylate, polyol(meth)acrylate, polyether(meth)acrylate, and melamine(meth)acrylate. Herein, the term “(meth)acryloyl group” implies any of an acryloyl group and a methacryloyl group. The term “oligomer” used herein implies a molecule having a molecular weight of 500 or more to 60000 or less.
A photopolymerization initiator used here can be selected, as appropriate, from among well-known materials. As examples of the well-known materials, benzophenone derivatives, acetophenone derivatives, anthraquinone derivatives, etc. can be used alone or in combination. An amount of the photopolymerization initiator mixed is preferably 0.1% by mass or more and 10% by mass or less of the solid content. If the amount is less than 0.1% by mass, photo-curability is reduced so that it is not suitable for industrial production from the practical point of view. On the other hand, if the amount exceeds 10% by mass, an odor tends to remain in a formed coating when an amount of light emitted for the irradiation is insufficient. Herein, the term “solid content” implies all components constituting the hard-coat layer 12 after being cured. Specifically, the solid content includes, for example, the acrylate, the photopolymerization initiator, etc.
Preferably, the resin has such a property that a structure can be transferred to the resin upon, e.g., irradiation of the energy ray or application of heat. Any type of resin, including a vinyl-based resin, an epoxy-based resin, a thermoplastic resin, etc., can be used as long as the resin satisfies the above-described requirements for the refractive index.
The resin may be mixed with an oligomer to reduce curing shrinkage. The resin may further contain polyisocyanate as a curing agent. In consideration of adhesion with the first optical layer 4 or the second optical layer 5, the resin may be further mixed with suitable one or more of monomers having a hydroxyl group, a carboxyl group and a phosphoric group; polyols; coupling agents such as carboxylic acid, silane, aluminum and titanium; and various chelating agents.
The resin composition preferably further contains a cross-linking agent. In particular, a cyclic cross-linking agent is preferably used as the cross-linking agent. It is because the resin can be made heatproof without greatly changing the storage elastic modulus at the room temperature by using the cross-linking agent. If the storage elastic modulus at the room temperature is greatly changed, the optical film 1 may become brittle so that it becomes difficult to manufacture the optical film 1 with the roll-to-roll process. Examples of the cyclic cross-linking agent include dioxaneglycol diacrylate, tricyclodecanedimethanol diacrylate, tricyclodecanedimethanol dimethacrylate, ethylene oxide-modified isocyanurate diacrylate, ethylene oxide-modified isocyanurate triacrylate, and caprolactone-modified tris(acryloxyethyl)isocyanurate.
Preferably, the first base 4a or the second base 5a has water vapor permeability lower than that of the first optical layer 4 or the second optical layer 5, respectively. For example, when the first optical layer 4 is formed by using the energy-ray curable resin, such as urethane acrylate, the first base 4a is preferably formed by using a resin having water vapor permeability lower than that of the first optical layer 4 and being transmissive to the energy ray, such as polyethylene terephthalate (PET). As a result, diffusion of moisture into the transflective layer 3 from the incidence surface S1 or the exit surface S2 can be reduced and deterioration of a metal, etc. contained in the transflective layer 3 can be suppressed. Hence, durability of the optical film 1 can be improved. Moreover, the water vapor permeability of PET having a thickness of 75 μm is about 10 g/m2/day (40° C., 90% RH).
Preferably, at least one of the first optical layer 4 and the second optical layer 5 contains a functional group having high polarity, and the content of such a functional group differs between the first optical layer 4 and the second optical layer 5. More preferably, both the first optical layer 4 and the second optical layer 5 contain a phosphoric compound (for example, phosphoric ester), and the content of the phosphoric compound differs between the first optical layer 4 and the second optical layer 5. The difference in the content of the phosphoric compound between the first optical layer 4 and the second optical layer 5 is preferably two or more times, more preferably five or more times, and even more preferably ten or more times.
From the viewpoint of giving the optical film 1, the window member 10, etc. a visually attractive design by using at least one of the first optical layer 4 and the second optical layer 5, it is preferable that it has a characteristic of absorbing light in a particular wavelength band within the visible range. A pigment dispersed in the resin may be either an organic pigment or an inorganic pigment. In particular, an inorganic pigment intrinsically having high resistance to weather is preferable. Specific examples of the pigment include: inorganic pigments including zircone gray (Co- and Ni-doped ZrSiO4), praseodymium yellow (Pr-doped ZrSiO4), chrome-titania yellow (Cr- and Sb-doped TiO2 or Cr- and W-doped TiO2), chrome green (such as Cr2O3), peacock blue ((CoZn)O(AlCr)2O3), Victoria green ((Al, Cr)2O3), deep blue (CoO.Al2O3.SiO2), vanadium-zirconium blue (V-doped ZrSiO4) chrome-tin pink (Cr-doped CaO.SnO2.SiO2), manganese pink (Mn-doped Al2O3), and salmon pink (Fe-doped ZrSiO4); and organic pigments including an azo-based pigment and a phthalocyanine pigment.
(Transflective Layer)
The transflective layer is a semitransmissive reflective layer. Examples of the semitransmissive reflective layer include a thin metallic layer, a metallic nitride layer, etc. containing a semiconductor material. Judging from the viewpoint of antireflection, tone adjustment, chemical wettability improvement, or reliability improvement against environmental deterioration, it is preferably formed as a laminate in which the above-mentioned reflective layer is laminated on or under an oxide layer, a nitride layer, an oxynitride layer, or the like.
Examples of the metallic layer with a high reflectance with respect to the visible region and the infrared region include materials whose main component is a single component selected from Au, Ag, Cu, Al, Ni, Cr, Ti, Pd, Co, Si, Ta, W, Mo, and Ge or an alloy containing two or more components selected from those. Further, Ag-based materials, Cu-based materials, Al-based materials, Si-based materials, or Ge-based materials are preferably used when taking utility into consideration. Moreover, materials such as Ti and Nd are preferably added to the metallic layer to suppress the corrosion of the metallic layer. Yet moreover, examples of the metallic nitride layer include TiN, CrN, and WN.
Though the film thickness of the transflective layer can be set to a range of 2 nm or more and 40 nm or less for example, the thickness is not limited thereto as long as the film thickness ensures a semitransmissivity in the visible region and the near-infrared region. The term “semitransmissivity” represents that the transmittance in a wavelength range of 500 nm or more and 1000 nm or less is 5% or more and 70% or less, preferably 100 or more and 60% or less, more preferably 15% or more and 55% or less. Moreover, the term “transflective layer” represents a reflective layer of which transmittance in a wavelength range of 500 nm to 1000 nm is 5% or more and 70% or less, preferably 10% or more and 60% or less, and even more preferably 15% or more and 55% or less.
(Function of Optical Film)
Moreover, as illustrated in
When it is assumed that an incidence angle of the light is α, a refractive index of the first optical layer 4 is n, a reflectance of the transflective layer 3 is R; a ratio x of a sky reflection component LA to a total incidence component is represented by the following expression (1).
x=(sin(45−α′)+cos(45−α′)/tan(45+a′))/(sin (45−α′)+cos(45−α′))×R2 (1)
Herein, α′=sin-1 (sin a/n).
The percentage at which the incident light is reflected to the sky decreases when the percentage of the component LB that is not reflected to the sky increases. An effective way to improve the percentage of the sky reflection is to devise the shape of transflective layer 3, i.e., the shape of the structure 4c in the first optical layer 4. For example, the shape of structure 4c is preferably set to a lenticular shape illustrated in
[Apparatus for Manufacturing Optical Film]
The laminate rolls 41 and 42 are disposed to be able to nip an optical layer 9 provided with a transflective layer, and the second base 5a. Herein, the optical layer 9 provided with the transflective layer is a layer obtained by depositing the transflective layer 3 on the principal surface of the first optical layer 4. In the optical layer 9 provided with the transflective layer, the first base 4a may be formed on one of two principal surfaces, the one principal surface being opposite to the principal surface on which the transflective layer 3 of the first optical layer 4 is deposited. In this example, the transflective layer 3 is deposited on one principal surface of the first optical layer 4, and the first base 4a is formed on the other principal surface. The guide roll 43 is disposed on a transportation path in the manufacturing apparatus so that a band-like optical film 1 can be transported. The materials of the laminate rolls 41 and 42 and the guide rolls 43 are not especially limited, and one appropriately selected from metals such as stainless, rubbers, and the silicones, etc. according to the desired roll characteristic can be used.
As the application device 45, for example, an application means such as a coater can be used. As the coater, for example, one such as a gravure device, a wire bar, and a mold can be appropriately used in consideration of physical properties and the like of the resin composition applied. The irradiation device 46 is a unit that emits an ionizing ray such as an electron beam, a ultraviolet ray, a visible light ray, or a gamma ray for example. In the example illustrated, a UV lamp that emits a ultraviolet ray is used as the irradiation device 46.
[Method of Manufacturing Optical Film]
Hereinbelow, an example of a method of manufacturing the optical film according to the first embodiment of the present invention will be described with reference to
First, as illustrated in
Moreover, as illustrated in
Next, the transflective layer 3 is deposited on one principal surface of the first optical layer 4 as illustrated in
Next, a resin 22 which is in an uncured state is coated over the transflective layer 3 as illustrated in
Hereinbelow, a method of forming the optical film 1 by using the manufacturing equipment illustrated in
Next, the transported second base 5a, and the optical layer 9 provided with the transflective layer are nipped by the laminate rolls 41 and 42 in such a way that bubbles do not enter between the second base 5a, and the optical layer 9 provided with the transflective layer, so that the optical layer 9 provided with the transflective layer is laminated on the second base 5a. Next, the optical layer 9 provided with the transflective layer laminated on the second base 5a is transported while it is brought into contact with the outer peripheral surface of the laminate roll 41, and the ionizing ray curable resin 44 is irradiated with the ionizing ray from the side including the second base 5a by the irradiation unit 46, so that the ionizing ray curable resin 44 is cured. As a result, the second base 5a, and the optical layer 9 provided with the transflective layer are affixed to each other with the ionizing ray curable resin 44 interposed therebetween, so that the optical film 1 having a desired length is manufactured. Next, the manufactured band-like optical film 1 is rolled by a winding-up roll (not illustrated). As a result, a master roll in which the band-like optical film 1 is wound is obtained.
When the process temperature during formation of the second optical layer is set to t° C., the cured first optical layer 4 preferably has a storage elastic modulus of 3×107 Pa or more at (t−20)° C. Here, the process temperature t represents, for example, a heating temperature of the laminate roll 41. Since the first optical layer 4 is disposed on the first base 4a and is transported along the laminate roll 41 with the first base 4a interposed therebetween for example, the temperature that is actually applied to the first optical layer 4 is about (t−20)° C. on an empirical basis. Therefore, by adjusting the storage elastic modulus of the first optical layer 4 at (t−20)° C. to 3×107 Pa or more, it is possible to suppress deformation of the concave-convex shape of the interface in the optical layer which is attributable to heat or a combination of heat and pressure.
The storage elastic modulus of the first optical layer 4 at 25° C. is preferably 3×109 Pa or less. As a result, the optical film becomes flexible at the room temperature. Accordingly, the optical film 1 can be manufactured by such a roll-to-roll manufacturing process.
The process temperature t is preferably 200° C. or below, considering the heat resistance of the optical layer or the resin used for the base. However, the process temperature t can be set to 200° C. or above when the resin with high heat resistance is used.
As described above, according to the optical film 1 according to the first embodiment, since the transflective layer 3 is formed on the concave-convex surface of the first optical layer 4, it is possible to block the sunlight including the visible light ray while suppressing glare and reflection. Moreover, since the second optical layer 5 encloses the concave-convex surface of the first optical layer 4 on which the transflective layer 3 is formed and thus the surface is preferably smoothed out, the transmission image becomes clearly visible.
<Modification>
Modifications of the above-described embodiment will be described below.
[First Modification]
[Second Modification]
As illustrated in
Moreover, by two-dimensionally arraying the structures 4c having a shape such as a spherical shape or a corner cube shape, as dense as possible, on a principal surface of the first optical layer 4, a dense array such as a cube dense array, a delta dense array, or a hexagonal dense array may be formed. A dense square array is an array in which the structures 4c each having a rectangular-shaped (for example, square-shaped) bottom are arrayed in a dense square form, that is, a matrix form (a grid form), for example, as illustrated in
The structures 4c are convex portions or concave portions, each having, for example, a corner cube shape, a hemispherical shape, a hemielliptic spherical shape, a prism shape, a cylindrical shape, a free curved surface shape, a polygonal shape, a conical shape, a polygonal pyramid shape, a truncated cone shape, a paraboloid shape, or the like. The bottom of the structures 4c has, for example, a circular shape, an elliptical shape, or a polygonal shape such as a triangular shape, a rectangular shape, a hexagonal shape, or an octagonal shape, etc. Pitches P1 and P2 of the structures 4c may be appropriately selected according to the desired optical properties. When a principal axis of the structure 4c is inclined with respect to a perpendicular line perpendicular to the incidence surface of the optical film 1, the principal axis of the structure 4c is preferably inclined in at least one array direction among two-dimensional array directions of the structures 4c. When the optical film 1 is affixed to the window member placed to be almost perpendicularly to the ground, the principal axis of the structure 4c is preferably inclined from the perpendicular line so as to face a lower portion (ground side) of the window member.
When the structure 4c has a corner cube shape and a ridge line R is large, it is preferable that the principal axis of the structure 4c is preferably inclined to face the sky. However, from the viewpoint of the purpose of suppressing the reflection toward the ground side, it is preferable that it is inclined to face down. As for solar rays, the light is difficult to be incident deep inside the structures because it is obliquely incident on the film, so that the shape of the structures on the incidence side is important. That is, when the R of a ridge line portion is large, the retroflector light decreases. Accordingly, in such a case, inclining the structure to face up the sky can suppress the phenomenon. Moreover, although the retroreflection can be achieved with a corner cube body by reflecting the light from the reflective surface three times, but a portion of the light leaks in directions other than the direction of the retroreflection over two times of reflections. A large amount of this leakage light can be returned in the direction of the sky by inclining the corner cube to face the ground side. In this way, it can be inclined to face in any direction depending on the shape and purpose.
According to the third embodiment, the plurality of transflective layers 3 is arrayed in parallel with each other in an optical layer 5. As a result, the number of reflections caused by the transflective layer 3 can be reduced compared to the case where the structures 4c having a corner cube shape or a prism shape are formed. Therefore, reflectance can be increased, and light absorption of the transflective layer 3 can be reduced.
A fourth embodiment is different from the first embodiment in that a portion of incident light is directionally reflected and a portion of the remainder of the light is scattered. An optical film 1 includes a light scattering body that scatters the incident light. For example, this scattering body is disposed at at least one location among on a surface of an optical layer 2, inside the optical layer 2, and between a transflective layer 3 and the optical layer 2. Preferably, the light scattering body is disposed at at least one location among on the surface of a first optical layer 4, in the first optical layer 4, and between the transflective layer 3 and the first optical layer 4. When the optical film 1 is affixed to a support, such as a window member etc., it is applied to any of the indoor side and the outdoor side. When the optical film 1 is of to the outdoor side, the light scattering body that scatters light is preferably disposed only between the transflective layer 3, and the support, such as the window member, etc. It is because the directional reflection property is lost when the light scattering body exists between the transflective layer 3 and the incidence surface. Moreover, when the optical film 1 is affixed to the indoor side, the light scattering body is preferably disposed between an exit surface which is a surface opposite to the surface to which the optical film 1 is affixed, and the transflective layer 3.
According to the fourth embodiment, a portion of the incident light is directionally reflected, and a portion of the remainder of the light can be scattered. Therefore, when the optical film 1 is clouded, a visually attractive design can be given to the optical film 1.
As described above, an optical film 1 is characterized in that it is transflective with respect to incident light. When the optical film 1 is used outdoors or in a dirty room where a lot of dirt exists, light is scattered due to the dirt adhering to the surface of the optical film 1 so that transmissivity and reflectivity are lost. Therefore, the surface of the optical film 1 is preferably optically transparent at all times. Therefore, it is preferable that the surface is superior in the water-repellent or hydrophilic property and the surface automatically develops the self-cleaning effect.
According to the fifth embodiment, since the optical film 1 includes the self-cleaning layer 51, the water-repellent property, the hydrophilic property, or the like can be imparted to the incidence surface. Therefore, it is possible to suppress dirt or the like from adhering to the incidence surface and to suppress degradation of the directional reflection characteristic.
The first embodiment has been described above, by way of example, in connection with the case of applying the present invention to a window member or the like. However, the application of the present invention is not limited to such an example but the present invention can be applied to various interior members or exterior members besides the window member. Moreover, the present invention is applicable not only to fixedly disposed interior and exterior members, such as walls and roofs, but also to a device which moves interior members or exterior members to adjust an amount of the transmitted and/or reflected sunlight depending on changes in amount of the sunlight, which are caused with the shift of seasons and the elapse of time, etc., and which can taken the adjusted amount of light in an indoor space, etc. In the sixth embodiment, one example of such a device is described in connection with a solar shading device (blind device) capable of adjusting an amount of incident light which is to be blocked by a solar shading member group including a plurality of solar shading members by changing an angle of the solar shading member group.
The head box 203 serves as a driving unit which rotates the slat group 202 including the plurality of slats 202a in accordance with operation of the operation unit, such as a rod, thereby adjusting the amount of light taken into an indoor space. Further, the head box 203 also functions as a driving unit (elevation unit) which moves the slat group 202 up and down, as appropriate, in accordance with operation of an operation unit, such as the elevation cord 207.
The base 211 can be formed in the shape of, for example, a sheet, a film, or a plate. Glass, resin material, paper, cloth, etc. can be used as a material of the base 211. In consideration of the case of taking visible light into a predetermined indoor space, a resin material having transparency is preferably used. The glass, the resin, the paper, and the cloth used here may be the same as that generally used in ordinary roll screens. The optical film 1 used here may be one type or a combination of two or more types of the optical films 1 according to the above-described first to fifth embodiments.
A seventh embodiment will be described in connection with a roll screen device which is another example of the solar shading device capable of adjusting an amount of incident light rays, which is to be blocked by a solar shading member, by winding or unwinding the solar shading member.
The base 311 can be formed in the shape of, for example, a sheet, a film, or a plate. Glass, resin material, paper, cloth, etc. can be used as a material of the base 311. In consideration of the case of taking visible light into a predetermined indoor space, for example, a resin material having transparency is preferably used. The glass, the resin, the paper, or the cloth used here may be the same as that generally used in ordinary roll screens. The optical film 1 used here may be one type or a combination of two or more types of the optical films 1 according to the above-described first to fifth embodiments.
An eighth embodiment will be described, by way an example, in connection with the case of applying the present invention to a fitting (for example, an interior or exterior member) that includes an optical body provided with a day-lighting portion, the optical body having directional reflection performance.
The base 411 is, for example, a sheet, a film, or a substrate that has flexibility. Glass, resin material, paper material, cloth material, etc. can be used as a material of the base 411. In consideration of the case of taking the visible light into a predetermined space, such as an indoor space, a resin material with transparency is preferably used. The glass, the resin material, the paper material, and the cloth material used here may be the same as that generally used as optical bodies in ordinary fittings. The optical film 1 used here may be one type or a combination of two or more types of the optical films 1 according to the above-described first to fifth embodiments.
Hereinbelow, the present invention will be described in detail in connection with Examples, but the present invention is not limited to the following Examples.
In the following Examples and Comparative Examples, a film thickness of a transflective layer which had been formed on a concave-convex surface of a first optical layer was measured in the following way.
First, an optical film was cut with an FIB (Focused Ion Beam) machine so that a cross section is exposed. Next, the cross section of this optical film was observed by a TEM (Transmission Electron Microscope), and a film thickness in a direction perpendicular to an inclined surface of a structure was measured at a center portion of the inclined surface of the structure. This measurement was repeatedly performed at 10 locations which were selected randomly within the same sample, the values of the measurements were simply averaged (that is, arithmetically averaged) to produce a mean film thickness, and this mean film thickness is used as a film thickness of the transflective layer.
First, a Ni—P-made mold roll that has minute V-shaped grooves illustrated in
Next, a resin composition having the following mixing ratio was coated over the transflective layer, a PET film (trade name: A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 75 μm was mounted thereon, and bubbles were purged out. After that, the resultant structure is irradiated with UV light so that the resin was cured. As a result, the resin composition between the smooth PET film and the transflective layer was cured, so that the resin layer (hereinafter, referred to as enclosing resin layer) was formed. As a result, an optical film of Example 1 which was intended to be obtained was obtained.
<Compounding of Resin Composition>
Urethane acrylate 99 parts by mass
(trade name: ARONIX, manufactured by Toagosei Co., Ltd., post-cure refractive index: 1.533)
2-acryloyloxy ethyl acid phosphate 1 parts by mass
(Light acrylate P-1A, manufactured by Kyoeisha Chemical Co., Ltd.)
An optical film of Example 2 was obtained in a similar manner to Example 1 except that an original board having a shape reversed to the shape (the minute cross V-shaped groove) illustrated in
An optical film of Example 3 was obtained in a similar manner to Example 1 except that minute triangular pyramids illustrated in
An optical film of Example 4 was obtained in a similar manner to Example 3 except that a transflective layer presented in Table 1 was used. A GAZO layer was deposited using a DC pulse sputtering method in which an oxide target having a composition of Ga2O3/Al2O3/ZnO=0.57 at %/0.31 at %/99.12 at was used, and 100% of argon gas was used as a sputtering gas.
An optical film of Example 5 was obtained in a similar manner to Example 3 except that a transflective layer presented in Table 1 was used.
An optical film of Example 6 was obtained in a similar manner to Example 3 except that a transflective layer presented in Table 1 was used.
An optical film of Example 7 was obtained in a similar manner to Example 3 except that a transflective layer presented in Table 1 was formed. An alloy target having a composition of Ag/Nd/Cu=99.0 at %/0.4 at %/0.6 at % was used for deposition of an AgNd Cu layer as a silver alloy layer.
An optical film of Example 8 was obtained in a similar manner to Example 3 except that a resin (trade name: ARONIX, manufactured by Toagosei Co., Ltd) having a post-cure refractive index of 1.542 was used for an upper layer (enclosing resin layer), and a difference in refractive index between a resin of an upper layer and a resin of a lower layer was set to 0.009.
An optical film of Example 9 was obtained in a similar manner to Example 5 except that a resin (trade name: ARONIX, manufactured by Toagosei Co., Ltd) having a post-cure refractive index of 1.540 was used as a material of an upper layer (enclosing resin layer), and a difference in refractive index between an upper layer (enclosing resin layer) and a lower layer (shaped resin layer) was set to 0.007.
An optical film of Comparative Example 1 was obtained by depositing a transflective layer having a film thickness presented in Table 1 on a PET film having a smooth surface.
An optical film of Comparative Example 2 was obtained by depositing a transflective layer having a film thickness presented in Table 1 on a PET film having a smooth surface.
An optical film of Comparative Example 3 was obtained in a similar manner to Example 3 except that a transflective layer presented in Table 1 is formed.
An optical film of Comparative Example 4 was obtained in such a way that processes up to a process of forming a transflective layer were similar to those in Example 3, but the top surface of the transflective layer had not been covered with a resin but had been exposed after obtaining a PET film having a shaped resin layer provided with the transflective layer.
An optical film of Comparative Example 5 was obtained in such a way that processes up to a process of forming a transflective layer were similar to those in Example 3, but the shaped surface on which the transflective layer is formed is applied with the same resin as the enclosed resin according to Example 1 after obtaining a PET film having a shaped resin layer provided with the transflective layer. Next, the UV light was irradiated upon N2 purge to avoid hardening inhibition caused by oxygen in a state in which the PET film is not formed on the coated resin so that the resin is cured. As a result, the optical film of Comparative Example 5 was obtained.
An optical film of Comparative Example 6 was obtained in a similar manner to Example 3 except that a resin (trade name: ARONIX, manufactured by Toagosei Co., Ltd.) having a post-cure refractive index of 1.546 was used for an upper layer (enclosing resin layer), and a difference in refractive index between an upper layer (enclosing resin layer) and a lower layer (shaped resin layer) is set to 0.013.
(Evaluation of Glare)
The optical films of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated for glare as follows.
The prepared optical films were of to glasses having a thickness of 3 mm with an optically transparent adhesive to prepare samples. Next, light of an indoor fluorescent lamp is reflected from the samples at an angle of about 30° with respect to a perpendicular axis of the samples, and the light of regular reflection was observed at a distance of 30 cm away from each of the samples. The observed light was evaluated by the following criteria, and the results are listed in Table 2.
∘: The fluorescent lamp exhibits the same degree of glare as the case where a single glass having a thickness of 3 mm is used;
x: The glare of the reflected light of the fluorescent lamp is strong so that it is difficult to look at the reflected light for a long time.
(Evaluation of Reflection)
The optical films of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated for reflection as follows.
The prepared optical films were off fixed to glasses having a thickness of 3 mm with an optically transparent adhesive.
Next, these glasses were installed in the environment of about 10001× in luminance, reflected images of the observer were observed at a distance of 2 mm away from the glasses. The observed images were evaluated by the following criteria. The results are listed in Table 2.
∘: The reflected image is almost the same in degree as that of the case of using only a glass having a thickness of 3 mm.
x: Because of the reflected image, the side over the glass is not visible.
(Evaluation of Visibility)
The optical films of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated for visibility as follows.
First, the prepared optical films were of fixed to glasses having a thickness of 3 mm with an optically transparent adhesive. Next, these glasses were held at a distance of about 50 cm away from eyes, and the next building's interior that existed over each glass in the distance of about 10 m was observed, and was evaluated by the following criteria. The results are listed in Table 2.
⊙: The ghost attributable to diffraction is not observed and the view is the same as that of the case of using an ordinary window.
∘: There is no problem under normal condition, but the ghost attributable to diffraction is observed when a specular reflector exists.
Δ: Objects and the shapes thereof are distinguished, but the ghost attributable to diffraction borders the observer.
x: Clouding occurs due to the effect of diffraction, so that the interior cannot be distinguished.
(Evaluation of Spectral Transmittance, Reflectance, and Chromaticity)
The optical films of Examples 1 to 9 and Comparative Examples 1 to 6 are evaluated for spectral transmittance and reflectance as follows.
The spectral transmittance and reflectance in the visible region and the near-infrared region were measured using DUV3700 manufactured by Shimadzu Corporation. In the measurement of transmittance, alight ray incidence angle to the samples were set to 0° (vertical incidence), and linear transmission light was measured. The spectrum transmittance waveforms are illustrated in
The transmission color tone was calculated from spectrophotometric data according to JIS Z8701 (1999) in which a D65 light source was used as a light source and 2° visual field was used. The results are listed in Table 2.
The visible light transmittance, solar transmittance, and solar reflectance were calculated from spectrophotometric data according to JIS A5759 (2008) except for the following (as for the solar reflectance calculation, JIS A5759 specifies incidence at 10° and measurement of regular reflection light. However, since the reflection light is reflected in a direction other than the direction of the regular reflection in the samples having directional reflectivity, such as the present films, the reflectance was measured using an integrating sphere). The results are listed in Table 2.
(Evaluation of Transmission Wavelength Unselectivity)
In order to determine whether both of the visible light and the infrared light are effectively blocked, the measurement result of the spectral transmittance was used. The transmittance at a wavelength of 500 nm was divided by transmittance at a wavelength of 1000 nm to calculate transmission wavelength unselectivity. The results are listed in Table 2.
(Evaluation of Directional Reflection)
A halogen light source 101 collimated to a parallelism of 5° or less was used, and the light that was reflected by a half mirror 102 was used as an incident light. Under such conditions, the light is emitted to a sample 103 as an optical film, and the directional reflection was detected with a spectroscope 104. The sample 103 was disposed to be inclined at 5° with respect to the incident light, the detector 104 performs scanning within a range of 0° to 90° (θm) while being rotated by 360° (φm) in the sample surface, the mean value of the reflection intensities with respect to wavelengths of 900 nm to 1550 nm was plotted in a polar coordinate. The results are illustrated in
Hereinbelow, the correspondence relation between the direction (θ, φ) of the directional reflection illustrated in
As described above, the direction (θ, φ) of the directional reflection illustrated in
θ: an angle formed by a perpendicular line l1 perpendicular to an incidence surface S1, and incident light L or reflected light L1,
φ: an angle formed by a specific linear line l2 in the incidence surface S1 and a component of the incident light L or the reflected light L1 projected on the incidence surface S1,
the specific linear line l2 in the incidence surface: an axis where an intensity of reflection in a direction φ becomes maximum when the incidence angle (θ, φ) is fixed, and a directionally reflective body 1 is rotated about the perpendicular line l1, serving as an axis, which is perpendicular to the incidence surface S1 of a sample 103 serving as an optical film.
On the other hand, measurement is performed by inclining the sample 103 with respect to the axis of the incident light ray, and the direction θm of the directional reflection is plotted with respect to the axis of the incident light ray in measuring the directional reflection of the present examples.
Moreover, when a rotational angle of the sample 103 during measurement is defined as φm, and when the direction φm=0° is not set aligned with l2 for cases of using some directions in which the sample 103 is installed during measurement, a compensation by the misaligned degree is necessary. Moreover, when the reflection direction θ of the light ray is minus based on the definition of the direction (θ, φ), the azimuth of (θ, φ) is converted so that θ become plus.
The correspondence relation between the direction (θ, φ) of the directional reflection, illustrated in
When the sample 103 is inclined with respect to the incident light by α°, the incident light L, the directionally reflected light L1, and the correspondence relation between the direction (θm, φm) of the directionally reflected light L2 and the direction (θ, φ) are represented as follows.
Here, the description is made specifically, by way of example, in connection with the direction of the directional reflection of Example 1.
As for the directional reflection of Example 1, though reflections occur in two directions, (θm, φm)=(7°, 0°) and (7°, 180°), since an angle of the incident light beam is θ=5°, and l2 direction is set aligned with φm=0°, the directions of the directional reflection become (5+7°, 0°)=(12°, 0°) and (5-7°, 0°)=(−2°, 0°)=(2°, 180°).
(Evaluation of Transmission Image Visibility)
The optical films of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated for transmission image visibility as follows. The transmission image visibility was evaluated by using optical combs having a comb width of 2.0 mm, 1.0 mm, 0.5 mm, and 0.125 mm, respectively, according to JIS-K7105. The measurement instrument used for this evaluation was an image clarity tester (ICM-1T type) manufactured by Suga Tester Ltd. Next, a total of the transmission image visibilities measured by using optical combs having a comb width of 2.0 mm, 1.0 mm, 0.5 mm, and 0.125 mm was calculated. The result is presented in Table 3. Moreover, a D65 light source was used as a light source.
(Evaluation of Haze)
The optical films of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated for haze as follows.
Haze was measured by using a haze meter HM-150 (manufactured by Murakami color Technical Research Institute) based on measurement conditions specified in JIS K7136. The results are listed in Table 3. A D65 light source was used as the light source.
(Measurement of Surface Roughness)
The optical film of Comparative Example 5 was evaluated for surface roughness as follows.
The roughness curve was acquired from a two-dimensional profile curve by using a stylus type surface profile measuring apparatus, ET-4000 (manufactured by Osaka laboratory), and an arithmetic mean roughness Ra was calculated. The measurement conditions were set according to JIS B0601:2001. The measurement conditions were shown as follows.
λc=0.8 mm
Evaluation length: 4 mm
Cutoff×5 times
Interval of data sampling: 0.5 μm
Table 1 shows construction of the optical films of Examples 1 to 9 and Comparative examples 1 to 6.
Table 2 shows evaluation results of the optical films of Examples 1 to 9 and Comparative Examples 1 to 6.
Table 3 shows evaluation results of the optical films of Examples 1 to 9 and Comparative Examples 1 to 6.
The follows are understood from the above evaluation results.
The incident light is directionally reflected in two directions because a prism shape and a crossed prism shape are used in Examples 1 and 2. On the other hand, the incident light is retroreflected in one direction because a corner cube shape is used in Examples 3 to 9.
In the optical films of Comparative Examples 1 and 2, since the reflective layer has a flat surface, glare and reflection are observed from the films.
In the optical film of Comparative Example 3, since the transflective layer is too thick, i.e. 100 nm in thickness, the transmission visibility has decreased.
In the optical film of Comparative Example 4, since the transflective layer is not enclosed by the enclosing layer, the visibility has decreased.
In the case of using the optical film of Comparative Example 4, the directional reflectivity is obtained for the near-infrared ray of a wavelength of about 1200 nm, and the visible light ray is transmitted. However, the transflective layer has not undergone transparency treatment such as formation of the enclosing resin layer, an object disposed over the optical film is not visible.
In the optical film of Comparative Example 5, it is difficult to completely smooth the surface when performing transparency treatment. For such a reason, in the case of using the optical film of Comparative Example 5, an object disposed over the optical film is not visible like the case of using the optical film of Comparative Example 4. From the fact that the pitch of the bottom edges of the triangular pyramid is 100 μm, the maximum height Rz is about 1.6 μm, and the arithmetic mean roughness Ra is 0.15 μm; it is understood that a smoother surface is necessary to make the transmission image appear more clearly.
In the optical film of Comparative Example 6, since a refractive index of the enclosing resin layer is 1.546 while a refractive index of the shaped resin layer is 1.533, the refractive index difference between them is excessively large, and thus the diffraction pattern is generated and the visibility has decreased.
As described above, in order to block the sunlight including visible light ray while suppressing glare and reflection, the transflective layer is preferably formed on the shaped resin layer.
In order to enable the transmission image to be clearly visible, it is preferable that the transflective layer is enclosed by the enclosing resin layer, the refractive index of the shaped resin layer and the refractive index of the enclosing resin layer are almost the same, and the surface of the enclosing resin layer is smooth.
Though the embodiments of the present invention have been described above in detail, the present invention is not limited to the above embodiments, and various modifications can be made thereto based on the technical idea of the present invention.
For example, the constructions, the methods, the shapes, the materials, and the numerical values mentioned above are presented only by way of example, and accordingly, different constructions, methods, shapes, materials, and numerical values, etc. may be used if necessary.
Each construction of the above-described embodiments can be combined with each other as long as it is not departing from the purport of the present invention.
Moreover, examples in which the blind devices and the roll screen devices are manually driven have been described in the embodiments, but the blind device and the roll screen devices may be electrically driven.
Moreover, though the constructions in which the optical film is affixed to an adherend such as a window member, etc. have been described as an example in the above embodiments, another construction may be adopted in which, as an adherend such as a window member, etc., the first optical layer or the second optical layer of the optical film is used itself. As a result, the function of the directional reflection can be imparted to an optical body such as a window member, etc. beforehand.
Moreover, for example, the above embodiments have been described in connection with the case where the optical body is an optical film. However, the shape of the optical body is not limited to a film, but it may be a plate, a block, or the like.
The above embodiments have been described in connection with the case where the present invention is applied to an interior member or an exterior member, such as a window member, a fitting, a slat of a blind device, a screen of a roll screen device, etc. However, the present invention is not limited by the examples, and can be applied to interior members or exterior members other than ones in the above examples.
Examples of the interior member or the exterior member to which an optical body according to the present invention is applied includes an interior member or an exterior member formed by an optical body itself, an interior member or an exterior member formed by a transparent bases to which a directionally reflective body is affixed, etc. When such an interior member or an exterior member is installed indoors, near a window, for example, it is possible to directionally reflect only an infrared ray toward the outside of an indoor space and to take visible light ray in the indoor space. Therefore, even when the interior member or the exterior member is installed, the necessity of the interior illumination is reduced. Moreover, since there is little scattering reflection toward the indoor side by the interior member or the exterior member, an increase in a surrounding temperature can be suppressed. Moreover, it also can be applied to a affix member other than the transparent base depending on the purpose, like the visibility control and the intensity improvement, etc.
Moreover, the above embodiments have been described in connection with the example in which the present invention is applied to the blind device and the roll screen device is described. However, the present invention is not limited to that example, but is applicable to various kinds of solar shading devices disposed indoors or outdoors.
Moreover, the above embodiments have been described in connection with the example in which the present invention is applied to a solar shading device (for example, roll screen device) which is capable of adjusting an amount of an incident light ray blocked by the solar shading member by winding up or winding off the solar shading member, but the present invention is not limited to that example. For example, the present invention is applicable to a solar shading device capable of adjusting an amount of an incident light lay blocked by the solar shading member by folding the solar shading member. Examples of the solar shading device include a pleated screen device that adjusts the amount of the blocked incident light by folding up a screen, serving as the solar shading member, into concertinas.
Moreover, the above embodiments have been described in connection with the example in which the present invention is applied to a horizontal blind device (Venetian blind device). However, the present invention is also applicable to a vertical blind device (vertical blind device).
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-025995 | Feb 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/053064 | 2/8/2011 | WO | 00 | 8/1/2012 |
