JP2016148853A - Lighting sheet, lighting device, and building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting sheet capable of achieving efficient lighting while suppressing direct radiation of sunlight, and making an outdoor side visible.SOLUTION: The lighting sheet includes a base layer and a light-deflecting layer. The light-deflecting layer includes: light-transmitting parts arranged in a plurality of numbers along a surface of the base layer; and a light-deflecting part disposed among the plurality of light-transmitting parts and filled with an ultraviolet-curable resin composition having a refractive index lower than that of the light-transmitting parts. Top and back surfaces of the light-deflecting layer in a portion where the light-transmitting parts are disposed are formed parallel to each other. In a cross section along a thickness direction of the light-deflecting part, an upper side line is formed into a polygonal line having a plurality of straight connected lines or into a curved line, and the upper side line is formed to protrude downward; and a lower side line is formed into a straight line at an angle of 0° or more and 30° or less with respect to the normal line of the sheet surface. In the upper side line, an angle formed by an end portion on a side where light exits, with respect to the normal line of the sheet surface is smaller than an angle formed by the lower side line with respect to the normal line of the sheet surface; and a recess is formed on a side line corresponding to an opening side between the light-transmitting parts, of side lines formed between the upper side line and the lower side line.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a daylighting sheet, a daylighting apparatus, and a building using the daylighting sheet for incorporating outside light such as sunlight into a building or the like.

  It is well known to use a so-called window glass to form a bright and comfortable indoor space by taking in outside light such as sunlight inside a building. On the other hand, however, if the outside light incident on the window glass is taken into the room as it is, there may be a problem such as feeling glare. On the other hand, several techniques for controlling the direct sunlight and adopting the indoor side in a more comfortable manner have been proposed.

  Patent Document 1 discloses a light control sheet for controlling sunlight intake arranged at a site where sunlight is taken into a building. This is composed of a light-transmitting part that transmits sunlight and a light-shielding part group that absorbs sunlight, and the light-shielding part group has a plurality of light-shielding parts arranged at a predetermined pitch in one direction in the sheet. .

  Patent Document 2 discloses a plate-shaped daylighting optical element provided at an opening of a building so as to take in sunlight. This is composed of a large number of prism parts arranged on the same plane, and the slope of each prism part transmits sunlight when the elevation angle of the sun is smaller than the critical elevation angle, and all the slopes when the elevation angle is greater than or equal to the critical elevation angle. The angle of reflection is such that the total amount of light collected when the elevation angle of the sun is greater than or equal to the critical elevation angle is less than the total amount of light harvested when it is less than the critical elevation angle.

JP 2010-259406 A JP 2003-157707 A

However, in the light control sheet having a configuration as disclosed in Patent Document 1, a part of the outside light (sunlight) is absorbed by the light shielding unit group, and thus the light control sheet is applied to a window of a building or the like. In this case, it is difficult to absorb the external light and effectively incorporate the external light into the room.
In addition, in the technique disclosed in Patent Document 2, it is possible to control light incident from the outside. However, since the image is refracted when viewed from the indoor side, it is clear for viewing the outside scenery. There was a shortage. Furthermore, the daylighting optical element disclosed in Patent Document 2 has a problem in durability because the prism-shaped unevenness is exposed to the indoor side, and is easily damaged depending on the installation location.

  In view of the above-described problems, an object of the present invention is to provide a daylighting sheet that is capable of suppressing direct sunlight (direct light) and efficiently daylighting so that the outdoor side can be seen from the indoor side. Moreover, the lighting apparatus and building using this are provided.

  The present invention will be described below.

  The invention according to claim 1 is a daylighting sheet in the form of a sheet disposed in a building opening so that the sheet surface is vertical, a sheet-like base material layer having translucency, and a base material layer And a light deflection layer that deflects light, and the light deflection layer includes a plurality of light transmission portions that transmit light arranged side by side along one surface of the base material layer, and a plurality of light transmission layers. And a light deflector filled with an ultraviolet curable resin composition having a refractive index lower than that of the light transmissive part, and the light deflection of the part where the light transmissive part is disposed. The front and back surfaces of the layers are formed in parallel, and the lighting sheet is arranged in the opening of the building, and the light deflection unit has a plurality of straight lines on the upper side of the lighting sheet in the thickness direction cross section. Is formed in a continuous polygonal line or curved shape, and the upper side is formed so as to protrude downward. The side on the lower side opposite to the side on the upper side is linear and is 0 ° or more and 30 ° or less with respect to the sheet surface normal of the daylighting sheet, and the side on the upper side The angle formed with respect to the sheet surface normal at the light emission side end is smaller than the angle formed with respect to the lower sheet surface normal, and the upper side and the lower side are Among the sides formed between the two, the daylighting sheet is provided with a concave portion on the side that becomes the opening between the light transmitting portions.

  The invention according to claim 2 is the daylighting sheet according to claim 1, wherein the downward convexity on the upper side side is such that the inclination angle with respect to the horizontal plane on the outdoor side of the upper side side is the indoor side. Is formed larger than the inclination angle with respect to the horizontal plane.

  The invention according to claim 3 is arranged so as to surround at least the periphery of the panel, the plate-like panel having translucency, the daylighting sheet according to claim 1 or 2 attached to one surface of the panel. A lighting device.

  The invention according to claim 4 is a building in which the daylighting device according to claim 3 is installed in an opening formed in a wall.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing the direct sunlight (direct light), it can light efficiently and it becomes possible to see the outdoor side from the indoor side.

It is a figure explaining a 1st form and is an external appearance perspective view of the building. It is the figure which looked at the lighting apparatus 10 from the front. It is a figure explaining the layer structure of the lighting panel. FIG. 5 is a diagram for explaining a form of a light deflection layer 23. FIG. 5A shows an example in which the side on the upper side of the optical deflection unit is a convex curve, and FIG. 5B shows the side on the upper side of the optical deflection unit formed by three straight lines. An example of a convex shape is shown below. This is an example in which the portion facing the outdoor side of the light deflection unit is concave. It is one figure explaining the effect of the daylighting sheet. It is another figure explaining the effect of the daylighting sheet. It is a figure explaining a 2nd form and is a figure explaining the layer structure of the lighting panel. It is a figure explaining the structure of the lighting panel of the test example 1. FIG. It is a figure explaining the structure of the lighting panel of the test example 2. FIG. It is a figure explaining the structure of the lighting panel of the test example 3. FIG.

  In each figure shown below, the structure may be exaggerated for easy understanding. In addition, for ease of viewing in each figure, a part of the reference numerals that are repeated may be omitted.

FIG. 1 is a diagram illustrating a first embodiment, and is an external perspective view of a building 1 provided with a daylighting sheet 20 (see FIG. 3). The building 1 is a so-called office building, and an outer wall facing the south side is provided with a plurality of openings that communicate indoors and outdoors, and a daylighting device 10 including a daylighting sheet 20 is disposed therein.
FIG. 2 is a front view of one daylighting apparatus 10 viewed from the outdoor side. As described above, the daylighting apparatus 10 includes the frame 11 and the daylighting panel 12 arranged in the frame of the frame 11, and is configured as a so-called window. And the said lighting device 10 is arrange | positioned at the opening part of the building 1 as mentioned above.

  FIG. 3 schematically illustrates the layer configuration of the daylighting panel 12 in the vertical section of the daylighting apparatus 10 taken along the line III-III in FIG. In FIG. 3, the lighting panel 12 is shown in a posture attached to the building 1 so that the panel surface is vertical. The left side of FIG. 3 is the outdoor side, the right side is the indoor side, the upper side is the top side, and the paper surface. The lower side is the ground side.

  As can be seen from FIG. 3, the daylighting panel 12 includes a panel 13 and a daylighting sheet 20 bonded to the inner side surface of the panel 13. The daylighting sheet 20 includes a hard coat layer 21, a base material layer 22, a light deflection layer 23, and an adhesive layer 26 from the indoor side. Hereinafter, each of these layers will be described.

  The panel 13 is a plate-shaped translucent panel having translucency used for a normal building or a vehicle window such as a glass panel or a resin panel. Therefore, a known plate glass or resin plate can be used as a member constituting the panel 13. The frame 11 described above is disposed at least around the panel 13, so that the daylighting panel 12 is attached within the frame 11.

The hard coat layer 21 is a layer provided on the outermost surface of the daylighting sheet 20 opposite to the panel 13 for the purpose of surface protection. The hard coat layer 21 can be formed as a transparent resin layer, and is preferably formed as a cured resin layer formed by curing a curable resin from the viewpoint of resistance to scratches and surface contamination.
Specifically, an ionizing radiation curable resin, other known curable resins, or the like may be appropriately employed according to the required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins. For example, acrylate-based ionizing radiation curable resins include monofunctional (meth) acrylate monomers, bifunctional (meth) acrylate monomers, (meth) acrylate monomers such as trifunctional or higher (meth) acrylate monomers, urethane (meta ) Acrylate, epoxy (meth) acrylate, polyester (meth) acrylate and other (meth) acrylate ester oligomers or (meth) acrylate ester prepolymers. Examples of tri- or higher functional (meth) acrylate monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

Further, the hard coat layer 21 may be added with a function of improving the stain resistance. This can be achieved, for example, by adding a silicone compound, a fluorine compound, or the like. Further, as other functions, it may have a function of improving antistatic properties and water repellency.
As a material that can be used for improving the antistatic property, PEDOT-PSS (PEDOT (Poly (3,4-ethylenedioxythiophene); 3,4-ethylenedioxythiophene polymer) and PSS (polynesulfonate) are used in the electron conduction type. ); A styrene sulfonic acid polymer)), and the ionic conductive type includes lithium salt materials.
Examples of materials that can be used to improve water repellency include fluorine compounds.

The base material layer 22 is a layer that becomes a base material for forming the light deflection layer 23.
Therefore, the base material layer 22 has a light transmitting property and supports the light deflection layer 23 so as to prevent deformation. From this point of view, as specific examples of the material constituting the base material layer 22, for example, a transparent resin mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, and the like, epoxy acrylate, urethane acrylate The reactive resin (ionizing radiation curable resin etc.) can be mentioned.

  Although the thickness of the base material layer 22 is not specifically limited, It is preferable that they are 25 micrometers or more and 300 micrometers or less. If the thickness of the base material layer 22 is out of this range, there is a risk of causing problems in workability. For example, if the base material layer 22 is too thin, wrinkles are likely to occur. Moreover, if the base material layer 22 is too thick, winding will become difficult in an intermediate process among the processes which manufacture the daylighting sheet 20. FIG.

The light deflection layer 23 has a light transmission part 24 and a light deflection part 25. The light transmitting portion 23 has a cross section shown in FIG. 3 and is disposed so as to extend in one direction along the surface of the base material layer 22 (horizontal direction in the posture disposed in the building 1). A plurality of light transmission portions 24 are arranged at a predetermined interval along the surface of the base material layer 22 in a direction different from the direction (vertical direction in the posture arranged in the building 1). In this embodiment, the adjacent light transmission parts 24 are connected and integrated at the end part on the base material layer 22 side.
On the other hand, the light deflection unit 25 is disposed between the adjacent light transmission units 24.

FIG. 4 shows an enlarged view of a part of the light deflection layer 23.
The light transmitting portion 24 is a portion that transmits light, and the surface on the base material layer 22 side and the opposite side surface (the surface on the adhesive layer 26 side) of the light deflection layer 23 where the light transmitting portion 24 is disposed. Are formed in parallel. This makes it easier to see the outdoor scenery through the daylighting sheet 20 as will be described later. Preferably, the light transmission part 24 transmits light without scattering. This improves the visibility of the backside scenery. Here, “transmits without scattering light” means a portion formed without adding a material that intentionally scatters, and inevitably occurs when light passes through the material. Scattering is allowed to occur.

  In this embodiment, the light transmitting portion 24 has a substantially trapezoidal cross section between the two light deflecting portions 25 in the cross section shown in FIGS. 3 and 4, and has a short upper bottom on the outdoor side and a long lower bottom on the indoor side. Sides constituting the interface with the deflecting unit 25 are leg portions. However, since the leg portion has a shape along the shape of the light deflection portion 25 described later, it is not necessarily a straight line.

Examples of the material constituting the light transmitting portion 24 include transparent resins mainly composed of one or more of acrylic, styrene, polycarbonate, polyethylene terephthalate, acrylonitrile, etc., and epoxy acrylate or urethane acrylate reactive resins (ionizing radiation). Curable resin).
Here, the refractive index of the material constituting the light transmitting portion 24 may be the same as or different from the refractive index of the base material layer 22. However, if there is a difference in refractive index between the two, the possibility of light being deflected at the interface increases, so even if they are the same material or different materials, the refractive index difference is small or there is no refractive index difference. It is preferable. Here, the refractive index of the material forming the light transmitting portion 24 is preferably in the range of 1.49 to 1.56, more preferably 1.49 to 1.50, from the versatility of the raw materials.

  The light deflection unit 25 is a part formed between two adjacent light transmission units 24. That is, as described above, the light transmission parts 24 are arranged in parallel in the direction along the sheet surface at a predetermined interval, and a concave portion having a predetermined shape is formed between the light transmission parts 24. The concave portion in the present embodiment is a groove having a cross-sectional shape corresponding to the cross-sectional shape of the light deflection unit 25 described later, and the light deflection unit 25 is formed by filling the material constituting the light deflection unit 25 therein. Yes. Accordingly, the light deflection unit 25 has a cross-sectional shape based on the recess.

The light deflecting unit 25 is a layer configured to be able to deflect the light irradiated here by totally reflecting the light. Therefore, the light deflection unit 25 is filled with a material having a lower refractive index than the light transmission unit 24. According to this, if the incident light satisfies the total reflection condition due to the difference in the refractive index between the light deflecting unit 25 and the light transmitting unit 24 and the angle of the light incident on the interface, the light is totally reflected here. Can be reflected and deflected. As will be described in detail later, the direction of the deflected light is changed, and for example, it can be eliminated from direct light that gives glare by irradiating the ceiling. The refractive index of the material forming the light deflection section 25 is preferably in the range of 1.49 to 1.56, more preferably 1.49 to 1.50, from the versatility of the raw materials.
Further, the refractive index difference between the light transmitting portion 24 and the light deflecting portion 25 at that time is 0.03 or more and 0.07 or less, more preferably 0.05 or more and 0.06 or less. In the range where the difference in refractive index is larger than 0 and smaller than 0.03, when wavelength dispersion during total reflection (dispersion due to different total reflection angles depending on the wavelength) occurs, long wavelength components are not totally reflected and short. Only the wavelength component may be totally reflected, which may cause a color change. On the other hand, if the difference in refractive index is larger than 0.06, the refractive index of the short wavelength component tends to be larger than the refractive index of the long wavelength refractive index component, and rainbow-like unevenness may be noticeable. is there.

Furthermore, in this embodiment, the light deflection unit 25 has the following shape. This will be described with reference to FIG.
The light deflection section 25 has a polygonal shape in the cross section shown in FIG. Among them, in the posture in which the daylighting panel 12 is arranged in the building 1, the upper side is formed so that the two sides 25a and 25b are continuous in the indoor / outdoor direction and protrude downward. That is, the side 25a is arranged on the outdoor side, and the side 25b is arranged on the indoor side.

When these two sides 25a, 25b are in the posture shown in FIG. 4, the angles of inclination thereof are different from each other with respect to the horizontal plane (the normal of the sheet surface of the daylighting sheet 20) θ _U1 and θ _U2 . doing. Here, θ _U1 and θ _U2 are inclined so as to be upward toward the outdoor side (sun side), and θ _U1 is set to an angle larger than θ _U2 . Thereby, in consideration of the altitude of the sun that varies depending on the season and time, it is possible to expand the scene in which sunlight can be totally reflected and deflected at the interface between the light transmission unit 24 and the light deflection unit 25. Therefore, it is preferable that the angle θ _U1 and the angle θ _U2 are also determined from this viewpoint. Details will be described later while showing an example of an optical path.
On the other hand, the side 25a, side edges 25d of the lower on the side opposite to the 25b, the inclination angle is the theta _D with respect to the horizontal plane (normal to the sheet surface of the lighting sheet 20). θ _D is not particularly limited, but is preferably 0 ° or more and 30 ° or less from the viewpoint of manufacturing.

The pitch at which the light deflection units 25 are arranged in parallel is not particularly limited, but is preferably 10 μm or more and 200 μm or less. If the pitch of the light deflecting portions 25 is too narrow, the shape becomes fine, so that processing becomes difficult during manufacturing. On the other hand, if the pitch of the light deflecting portions 25 is too wide, the releasability of the material tends to be lowered when molding with a mold.
Moreover, the size of the outdoor side (opening side of the concave portion between the light transmitting portions on the side opposite to the base material layer 22) in the cross section of the light deflection portion 25 is not particularly limited, but is preferably 5 μm or more and 150 μm or less. . If this width is too narrow, it becomes a fine shape, making processing difficult. On the other hand, if this width is too wide, the releasability of the material tends to decrease when molding with a mold.

  The size of the light deflection unit 25 in the thickness direction (the left-right direction in FIG. 4) is not particularly limited, but is preferably 10 μm or more and 200 μm or less. If this is too small, it may be difficult to process the light deflection section 25 itself. On the other hand, if this is too large, the manufacture of the mold for forming the light deflection section 25 and the releasability of the material from the mold may be reduced, and the productivity may be deteriorated.

5 and 6 show cross-sectional shapes of the light deflection unit according to the modification.
FIG. 5A shows an example of the light deflection unit 25 ′ whose upper side is convex downward. In this example, the inclination angle of the tangent line at the most outdoor part is an angle θ _{U1 with} respect to the horizontal plane (the normal of the sheet surface of the daylighting sheet 20), and the inclination angle of the tangent line at the most indoor part is horizontal (lighting). The angle θ _U2 may be set with respect to the normal of the sheet surface of the sheet 20.
FIG. 5B shows an optical deflector 25 ″ whose upper side is formed by three sides 25 ″ a, 25 ″ c, 25 ″ b from the outdoor side and is convex downward. It is an example. In this example, the inclination angle of the side 25 ″ a that is the outermost side is an angle θ _{U1 with} respect to the horizontal plane (the normal of the sheet surface of the daylighting sheet 20), and the inclination angle of the side 25 ″ b that is the innermost side. Is an angle θ _{U2 with} respect to the horizontal plane (the normal of the sheet surface of the daylighting sheet 20), and the inclination angle of the side 25 ″ c arranged therebetween is relative to the horizontal plane (the normal of the sheet surface of the daylighting sheet 20). It is preferable that the angle θ _U3 and θ _U2 <θ _U3 <θ _U1 .
Here, the example of the light deflection unit including the three sides 25 ″ a, 25 ″ c, and 25 ″ b has been described, but the present invention is not limited thereto, and the light deflection unit may be formed by more sides.

  These light deflecting units as shown in FIGS. 5A and 5B also have the same effect as the light deflecting unit having the shape shown in FIG. Further, according to the shapes shown in FIGS. 5A and 5B, it is possible to suppress the occurrence of rainbow-like unevenness due to wavelength dispersion due to total reflection.

  FIG. 6 shows an example of the light deflecting portion 25 ″ in which the opening side of the groove formed between the light transmitting portions (in this embodiment, the side facing the outdoor side) is recessed. 'Represents. In this case, the adhesive of the adjacent adhesive layer 26 is filled inside the recess. According to this, sunlight can be further deflected in the concave portion to control the light.

  In addition, from the viewpoint of scattering the totally reflected light, the interface between the light deflecting unit 25 and the light transmitting unit 24 may be a mat surface that is a surface on which countless minute irregularities are formed.

  In this embodiment, the side 25d is a straight line, but the shape of the lower side is not limited to this, and may be formed to be the same as the upper side (mirror target). Good.

Returning to FIG. 3, the description of other configurations will be continued.
The adhesive layer 26 is a layer for adhering the daylighting sheet 20 to the panel 13. The material constituting the adhesive layer 26 is not particularly limited as long as it can adhere the daylighting sheet 20 to the panel 13, and a known pressure-sensitive adhesive, adhesive, photocurable resin, thermosetting resin, or the like is used. it can. As a more specific example, for example, an acrylic pressure-sensitive adhesive can be used as the adhesive layer 26, and more specifically, a pressure-sensitive adhesive in which an acrylic copolymer and an isocyanate compound are combined. However, the material constituting the adhesive layer 26 is preferably made of a material excellent in translucency and weather resistance due to the properties of the daylighting sheet 20.

  The thickness of the adhesive layer 26 is not particularly limited, but is preferably 10 μm or more and 100 μm or less. If the adhesive layer 26 is too thin, the adhesion between the panel 13 and the daylighting sheet 20 may be reduced. If the adhesive layer 26 is too thick, it is difficult to make the thickness of the adhesive layer 26 uniform.

The daylighting device 10 is formed by the daylighting panel 12 including the daylighting sheet 20 described above, and this is arranged in the opening of the building 1 as shown in FIG. Next, the action in the scene where the daylighting sheet 20 is arranged in this way and the preferable values of the angles θ _U1 and θ _U2 described above will be described based on main optical paths. Examples of optical paths necessary for the explanation are appropriately shown in the drawings shown below. Note that the optical path examples shown in each drawing are conceptual and do not strictly represent the degree of refraction or reflection.

FIG. 7 shows light L _S1 from the sun S as an example of one optical path. As can be seen from FIG. 7, L _S1 is applied to the daylighting panel 12 at an elevation angle (an angle formed from a horizontal plane) θ _S1 based on the solar altitude at that time. The light L _S1 incident on the daylighting panel 12 travels through the light transmitting portion 24 of the light deflection layer 23 while passing through the daylighting panel 12. In the light transmission part 24, if the refractive index of the light transmission part is N _P and the outdoor refractive index is N ₀ , the light L _S1 travels at the sunlight advancing angle θ _P1 represented by the equation (1). .

When the sunlight traveling at the sunlight traveling angle θ _P1 reaches a part of the interface between the light transmitting unit 24 and the light deflecting unit 25 with an inclination angle of θ _U2 , the light transmitting unit 24 and the light deflecting unit 25 If the relationship between the refractive index difference and the sunlight traveling angle θ _P1 is equal to or greater than the total reflection critical angle, total reflection occurs at the interface as shown in FIG. As a result, sunlight is deflected and direct light that causes glare can be suppressed.

FIG. 8 shows light L _S2 from the sun S, which is another example of the optical path. As can be seen from FIG. 8, L _S2 is applied to the daylighting panel 12 at an elevation angle (angle formed from a horizontal plane) θ _S2 based on the solar altitude at that time. Here, θ _S2 is an angle larger than θ _S1 . The light L _S2 incident on the daylighting panel 12 travels through the light transmitting portion 24 of the light deflection layer 23 while passing through the daylighting panel 12. In the light transmission part 24, if the refractive index of the light transmission part is N _P , and the outdoor refractive index is N ₀ , the light L _S2 travels at the sunlight advancing angle θ _P2 expressed by the equation (2). .

In this example, when the sunlight traveling at the sunlight traveling angle θ _P2 reaches a portion of the interface between the light transmitting portion 24 and the light deflecting portion 25 where the inclination angle is θ _U1 , the light transmitting portion 24 and the light deflection If the relationship between the refractive index difference with the portion 25 and the sunlight traveling angle θ _P1 is equal to or greater than the total reflection critical angle, total reflection is performed at the interface as shown in FIG. As a result, the light transmission unit 24 is advanced at an angle smaller than the sunlight traveling angle θ _P2 , and further reaches a portion where the inclination angle disposed indoors is θ _U2 and is totally reflected here. As a result, sunlight is deflected and direct light that causes glare can be suppressed.
That is, in this example, sunlight is totally reflected and deflected twice at a portion where the inclination angle is θ _U1 and a portion where the inclination angle is θ _U2 in the interface between the light transmission portion 24 and the light deflection portion 25, Prevents direct light that causes glare.
If the inclination angle of the light deflecting unit is θ _U2 throughout, L _S2 is incident on the light transmitting unit at a large elevation angle (sunlight traveling angle) θ _P2 , so the light deflecting unit and the light transmitting unit The light cannot be totally reflected at the interface with the light, and is transmitted, and enters the room as direct light.
On the other hand, according to the light deflecting unit 25, it is possible to deflect such sunlight L _{S2 so} that it is totally reflected and does not become direct light.

As can be seen from the above, according to the daylighting sheet 20, as long as the inclination angles θ _U1 and θ _U2 have a relationship of θ _U1 > θ _U2 , sunlight having different traveling angles such as light L _S1 and L _S2. Can be provided indoors by deflecting it with total reflection, and without greatly reducing the amount of sunlight entering the room, and eliminating at least some direct light (so-called direct sunlight) Is possible. Thereby, a bright and comfortable indoor space can be formed.

Further, the daylighting sheet 20 is provided with the light transmission part 24 as described above, and the front and back surfaces of the light deflection layer 23 at the part where the light transmission part 24 is arranged are formed in parallel and smooth. As a result, as shown in FIG. 7, the light L _K1 with the outdoor scenery can enter the room with almost no distortion, which means that the outdoor scenery can be visually recognized from the indoor side. . Therefore, the daylighting sheet 20 has a structure that makes it easier to visually recognize the scenery outside the room.

Here, the deflected direction depends on the sunlight traveling angle θ _P that is an angle incident on the interface and θ _U1 and θ _U2 that are the inclination angles of the light deflecting unit. Therefore, it is preferable that θ _U1 and θ _U2 are determined so that the totally reflected light finally becomes upward from the horizontal.

Further, according to the daylighting sheet 20 as described above, if θ _U1 > θ _U2, it is possible to eliminate at least part of the direct light while efficiently incorporating sunlight. However, it is possible to define θ _U1 and θ _U2 that are more preferable from the viewpoint of more effectively totally reflecting the sunlight by the light deflecting unit 25 and deflecting and emitting the sunlight to the indoor side. This will be described in detail below.

As can be seen from the above optical path example, θ _U1 can set an angle at which the sunlight incident on the daylighting sheet can be appropriately totally reflected when the elevation angle of the sun is high. For example, the elevation angle θ _SH when the south-high altitude is highest in one year can be set. That is, since the sunlight advancing angle θ _PH in the light transmission portion when the elevation angle θ _SH is set is expressed by the following equation (3), θ _U1 can be totally reflected so that light traveling at this angle θ _PH can be totally reflected. Set.

However, elevation theta _SH is differs by latitude and a predetermined region extending so as to straddle the different latitudes (e.g. country or region, etc.) theta _SH1 to theta _SH2 in (theta _SH1 <theta _SH2), defining a range of theta _U1 be able to. That is, Formula (4) can be made into the preferable range of (theta) _U1 .

Here, in Japan, θ _SH in Sapporo is 70.5 °, and θ _SH in Okinawa is 87.5 °. Therefore, it is preferable that θ _U1 be in the range of equation (5).

On the other hand, as can be seen from the above optical path example, θ _U2 can set an angle at which sunlight incident on the daylighting sheet can be appropriately totally reflected when the elevation angle of the sun is low. For this, for example, the elevation angle θ _SL when the altitude is the lowest in one year can be set. That is, since the sunlight advancing angle θ _PL in the light transmitting portion when the elevation angle θ _SL is set is expressed by the following equation (6), θ _U2 is able to totally reflect the light traveling at this angle θ _PL. Set.

However, since the elevation angle θ _LH varies depending on the latitude, the range of θ _U2 is defined by θ _{SL1 to} θ _SL2 (θ _SH1 <θ _SH2 ) in a predetermined region (for example, a country or a region) that extends across different latitudes. be able to. Here, since θ _U2 becomes smaller than 0 ° (inclined as opposed to FIG. 4), it becomes difficult to manufacture, so that it is preferably 0 ° or more. Thus, Equation (7) can be set to a preferable range of _θU2 .

Here, in Japan, θ _SL in Okinawa is 40.5 °, and therefore θ _U2 is preferably in the range of equation (8).

  The daylighting sheet 20 may be provided with a configuration for adding another function to any of the above-described layers. For example, an ultraviolet absorber, a heat ray absorber, or a near infrared absorber may be added to provide an ultraviolet ray absorbing function, a heat ray absorbing function, or a near infrared ray absorbing function.

  The near-infrared absorbing function can be improved by adding or applying a near-infrared absorbing agent (near-infrared absorbing dye) to one or more of the above layers. As the near-infrared absorbing dye, it is preferable to use one that absorbs a wavelength region of 800 nm to 1100 nm. The near-infrared transmittance in the wavelength region is preferably 20% or less, and more preferably 10% or less. On the other hand, the near-infrared absorbing dye preferably has a sufficient transmittance in the visible light region, that is, in the wavelength region of 380 nm to 780 nm.

  The ultraviolet absorbing function can be improved by adding or applying an ultraviolet absorber exemplified below to one or more of the above layers. Examples of ultraviolet absorbers include benzotriazole ultraviolet absorbers (TINUVIN P, TINUVIN P FL, TINUVIN 234, TINUVIN 326, TINUVIN 326 FL, TINUVIN 328, TINUVIN 329, TINUVIN 329 FL, all manufactured by BASF Japan Ltd.), and triazine. Ultraviolet absorber (TINUVIN 1577 ED, manufactured by BASF Japan Ltd.), benzophenone ultraviolet absorber (CHIMASSORB 81, CHIMASORB 81 FL, all manufactured by BASF Japan Ltd.), benzoate ultraviolet absorber (TINUVIN 120, BASF Japan Ltd.) Manufactured).

  The heat ray absorbing function can be improved by adding or applying a heat ray absorbent exemplified below to one or more of the above-described layers. Examples of the heat ray absorbent include metal oxide ultrafine particles such as antimony-doped tin oxide (ATO) or tin-doped indium oxide (ITO) and phthalocyanine compounds.

  The daylighting panel 12 described above is manufactured as follows, for example. That is, the daylighting panel 12 can be manufactured by bonding the daylighting sheet 20 to the panel 13. Here, the daylighting sheet 20 can be manufactured as follows, for example.

  The light deflection layer 23 of the daylighting sheet 20 can be formed by a method using a mold roll. That is, a mold roll is prepared in which irregularities capable of transferring the light transmitting portion 24 of the light deflection layer 23 are provided on the outer peripheral surface of the cylindrical roll. And the base material used as the base material layer 22 is inserted between a die roll and the nip roll arrange | positioned so as to oppose this. And a mold roll and a nip roll are rotated, supplying the composition which comprises the light transmissive part 24 between one surface and a mold roll among base materials. As a result, the concave / convex concave portions formed on the surface of the mold roll are filled with the composition constituting the light transmitting portion 24, and the composition conforms to the concave / convex surface shape of the mold roll.

  Here, as a composition which comprises the light transmissive part 24, what was mentioned above is preferable, However, A more specific example is as follows. That is, the photocurable resin composition which mix | blended the reactive dilution monomer (M1) and the photoinitiator (I1) with the photocurable prepolymer (P1) can be used.

  Examples of the photocurable prepolymer (P1) include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.

  Examples of the reactive dilution monomer (M1) include vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy acrylate, and tetrahydrofurfuryl acrylate.

  Examples of the photopolymerization initiator (I1) include hydroxybenzoyl compounds (2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin alkyl ether, etc.), benzoyl Formate compounds (such as methylbenzoylformate), thioxanthone compounds (such as isopropylthioxanthone), benzophenones (such as benzophenone), phosphate compounds (1,3,5-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-) Trimethylbenzoyl) -phenylphosphine oxide and the like, and benzyldimethyl ketal and the like. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected. From the viewpoint of preventing the light transmitting portion 16 from being colored, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone and bis (2,4,6-trimethylbenzoyl) are preferable. ) -Phenylphosphine oxide.

  These photocurable prepolymer (P1), reactive diluent monomer (M1) and photopolymerization initiator (I1) can be used alone or in combination of two or more.

  Light is irradiated from the base material side by a light irradiation device to the composition constituting the light transmission part 24 sandwiched between the mold roll and the base material and filled therein. Thereby, the composition which comprises the light transmissive part 24 can be hardened, and the shape can be fixed. And the base material layer 22 and the shape | molded light transmission part 24 are released from a metal mold | die roll with a mold release roll.

  Next, the light deflecting portion can be formed by filling the concave portion of the light transmitting portion 24 with the composition constituting the light deflecting portion 25 and curing it. In this manner, the light deflection layer 23 can be formed on the base material layer 22.

  An adhesive is laminated on the light deflection layer 23 thus formed to form an adhesive layer 26, and the hard coat layer 21 is attached to the base material layer 22 with an adhesive or the like. Thereby, the daylighting sheet 20 is obtained.

  FIG. 9 is a diagram for explaining the second embodiment and corresponds to FIG. In the second embodiment, the daylighting sheet 120 having the light deflection layer 123 to which the light deflection unit 125 is applied instead of the light deflection unit 25 is formed. The daylighting sheet 120 is affixed to the panel 13 to become the daylighting panel 112. Accordingly, in the daylighting sheet 120, the light deflection unit 125 is applied instead of the light deflection unit 25, and other configurations are the same as those of the daylighting sheet 20. Therefore, the light deflection unit 125 will be described here, and the other configurations are the same. The reference numerals are attached and the description is omitted.

In addition to the form of the light deflection unit 25, the light deflection unit 125 is filled with a material for scattering and reflecting or transmitting light. The material for scattering the light is not particularly limited, and examples of the scattering reflection include a curable resin mixed with a light scattering agent such as a white pigment or a silver pigment. Examples of the white pigment include metal oxides such as titanium oxide, titanium dioxide, magnesium oxide, and zinc oxide. As a silver pigment, metals, such as aluminum and chromium, are mentioned, for example. Thereby, light can be efficiently scattered and reflected. The curable resin may be the same as the material constituting the light transmission part 24.
On the other hand, regarding the configuration for scattering reflection and scattering transmission, the light deflection unit 125 can be formed of a material obtained by mixing a transparent binder resin and a transparent scattering agent having a refractive index different from that of the binder resin. As the transparent binder resin, the same resin as the light transmitting portion 24 can be used. On the other hand, examples of the transparent scattering agent include cross-linked particles obtained by polymerizing monomers mainly composed of (meth) acrylic acid ester and styrene. Specific examples of the crosslinked particles include Gantz Pearl (registered trademark) manufactured by Gantz Kasei Co., Ltd. The cross-linked particles can be controlled in refractive index by changing the mixing ratio of acrylic acid ester and styrene. For example, the refractive index can be made about 1.49 by increasing the acrylic ratio, and the refractive index can be made about 1.59 by increasing the styrene ratio. Further, urethane cross-linked particles can be used as the scattering agent. Specific examples of the urethane cross-linked particles include Art Pearl (registered trademark) manufactured by Negami Kogyo Co., Ltd. The scattering agent can also be hollow particles.

In the daylighting sheet 120 having such a light deflection unit 125, light can be guided like sunlight L _S3 in addition to the optical paths such as L _S1 and L _S2 described above. FIG. 9 shows the optical path of L _S3 .
As can be seen from FIG. 9, L _S3 is applied to the daylighting panel 112 at an elevation angle (angle formed from a horizontal plane) θ _S3 based on the solar altitude at that time. The light L _S3 incident on the daylighting panel 112 travels through the light transmitting portion 24 of the light deflection layer 123 while passing through the daylighting panel 112. In the light transmission part 24, if the refractive index of the light transmission part is N _P and the outdoor refractive index is N ₀ , the light L _S3 travels at the sunlight advancing angle θ _P3 represented by the equation (9). .

When the sunlight traveling at the sunlight traveling angle θ _P3 reaches a part of the interface between the light transmitting unit 24 and the light deflecting unit 125 whose inclination angle is θ _U2 , the light transmitting unit 24 and the light deflecting unit 125 If the relationship between the difference in refractive index and the sunlight traveling angle θ _P3 is equal to or smaller than the total reflection critical angle, the light travels beyond the interface as shown in FIG. Here, since the light deflecting unit 125 can scatter and emit the light to the indoor side, it is possible to suppress direct light that causes sunlight to scatter and cause glare.

  Thus, in the daylighting sheet 120, the light that has entered the light deflection unit without being totally reflected depending on the conditions of the incident light can be scattered and not emitted directly, but can be emitted indoors.

  In the conventional technology, there is a case in which sunlight does not diffuse and there is a lot of light that reaches the room directly (direct light), and there is a problem that a person in the room feels glare. As a result, even if the room becomes brighter, curtains and blinds are used to prevent glare and the room becomes dark. According to the present invention, this can be suppressed, and glare can be prevented without darkening the room as in the prior art.

In each of the following test examples, an example in consideration of the South-China altitude in Tokyo will be described. In Tokyo, the elevation angle θ _{SH at} the highest south-middle altitude of the year is 78 °, and the elevation angle θ _{SL at} the lowest south-middle altitude of the year is 31 °.
The refractive index of the light transmitting portion to be used in each test example is _{N p} 1.550, the refractive index of the light deflection unit is 1.490. Therefore, when the elevation angle is θ _SH , the advance angle of sunlight (sunlight advance angle) θ _P traveling inside the light transmission portion is 39.1 °, and when the elevation angle is θ _SL , the advance angle of sunlight traveling inside the light transmission portion (sun Light traveling angle) θ _P is 19.4 °.

  In Test Example 1, a daylighting panel according to an example of the daylighting panel 12 including the daylighting sheet 20 was produced. FIG. 10 and Table 1 show the shape of the light deflection layer in Test Example 1. As can be seen from the above, in Test Example 1, the upper side of the light deflection unit was configured with two sides having different angles in cross section.

In this example, the light deflection layer was produced as follows.
(1) Preparation of light transmission part constituent composition First, bisphenol A ethylene oxide / xylylene diisocyanate / phenoxyethyl acrylate / 2-hydroxyethyl acrylate / bismuth tri (2-ethylhexanoate) is 30: 15: 50: 5: 0. The mixture was mixed at 02 and reacted at 80 ° C. for 10 hours to obtain a photocurable prepolymer (P1).
On the other hand, bisphenol A ethylene oxide / isophorone diisocyanate / phenoxyethyl acrylate / bismuth tri (2-ethylhexanoate) was mixed at 30: 20: 50: 0.02 and reacted at 80 ° C. for 10 hours to produce a photocurable prepolymer ( P2) was obtained.
Next, 30 parts by mass of the photocurable prepolymer (P1), 30 parts by mass of the photocurable prepolymer (P2), 10 parts by mass of phenoxyethyl acrylate as the reactive dilution monomer (M1), the reactive dilution monomer 30 parts by mass of bisphenol A ethylene oxide as (M2), 0.03 parts by mass of phosphate ester of 10 mol of tetradecanol ethylene oxide as mold release agent (S1), mold release agent (S2) 0.03 part by mass of stearylamine ethylene oxide 15 mol adduct as 1 part, and 1 part by weight of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufacturer name: BASF) as a photopolymerization initiator (I1), It homogenized and the light transmissive part composition was obtained.
The light transmitting part constituting composition was applied at a thickness of 100 μm, and the light transmitting part constituting composition was cured by irradiating an ultraviolet ray of 800 mJ / cm ² with a high pressure mercury lamp. Using ATAGO Co., Ltd., the refractive index of 589 nm was measured and found to be 1.550.

(2) Substrate As the substrate, PET film, trade name: A4300, manufactured by Toyobo Co., Ltd., thickness of 100 μm was used.

(3) Production of mold roll A mold roll used for production of the light deflection layer was produced. The mold roll was cylindrical and was plated with copper, and the copper plated portion was cut with a cutting tool to form a groove corresponding to the light transmitting portion. A diamond tool was used as the tool. Grooves were formed by cutting the outer periphery of the copper plating layer of the mold roll at a predetermined pitch in the roll axis direction. The cut roll was chrome plated.

(4) Formation of light transmission part The base material of said (2) was conveyed between the metal mold | die roll and nip roll produced by said (3). In accordance with the conveyance of the base material, the light transmitting portion constituting composition obtained in (1) above is supplied from the supply device onto the base material layer of the base material, and the base material is pressed by the pressing force between the mold roll and the nip roll. The light transmitting portion constituting composition was filled between the layer and the mold roll. Then, 800 mJ / cm < ² > of ultraviolet rays were irradiated from the base material side with the high pressure mercury lamp, the light transmissive part constituent composition was hardened, and the light transmissive part was formed. Then, the light transmission part was released from the mold roll with a peeling roll to produce a sheet (intermediate member) including the light transmission part.
The elastic modulus of the light transmitting portion was measured by applying a load to the micro indenter material using a compression micro hardness tester (FISCHER HM2000) and unloading the material. At this time, the load force was 100 mN, the load speed was 4 μm / 10 seconds, and the holding time was 60 seconds. As a result, the elastic modulus of the light transmission part was 800 MPa.

(5) Preparation of composition composition of light deflection part 42 parts by mass of urethane acrylate as photocurable prepolymer (P3), 18 parts by mass of epoxy acrylate as photocurable prepolymer (P4), reactive dilution monomer (M3) 35 parts by weight of tripropylene glycol diacrylate as a reactive monomer, 5 parts by weight of methoxytriethylene glycol acrylate as a reactive diluent monomer (M4), 5 parts by weight of titanium oxide as a light scattering agent (D1), a photopolymerization initiator 7 parts by mass of 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, manufacturer name: BASF) as (I1) was mixed and homogenized to obtain a light deflector composition composition.
The components excluding the light scattering agent in the composition of the light deflector are coated at a thickness of 100 μm, cured by irradiating with 800 mJ / cm ² of ultraviolet light with a high-pressure mercury lamp, and a multi-wavelength Abbe refractometer (stock) The refractive index of 589 nm was measured using a product of Atago Co., Ltd. and found to be 1.490.

(6) Formation of light deflection part The composition composition of the light deflection part obtained in (5) above was supplied from the supply device onto the intermediate member produced in (4) above. In addition, using a doctor blade arranged substantially perpendicular to the traveling direction of the intermediate member, the light deflection unit constituent composition supplied onto the intermediate member is placed in a groove (groove between the light transmitting portions) formed in the intermediate member. While filling, the excess light deflector composition was scraped off. Thereafter, the composition of the light deflection unit was cured by irradiating with 800 mJ / cm ² of ultraviolet light from a high pressure mercury lamp to form a light deflection unit. In this state, a recess having a depth of 6 μm was generated on the surface of the light deflection unit. When the above process was performed once more, a depression having a depth of 3 μm was generated on the surface of the light deflection section.

(7) Formation of adhesive layer 100 parts by mass of an acrylic resin adhesive (trade name: SK Dyne 2094, Soken Chemical Co., Ltd., solid content 25.0%, solvents are ethyl acetate and methyl ethyl ketone), and a crosslinking agent (E -5XM, L-45, Soken Chemicals Co., Ltd., solid content 5.0%) 0.28 mass%, 1,2,3-benzotriazole 0.25 mass parts, diluent solvent (toluene / methyl ethyl ketone / Cyclohexanone = 27.69 g / 27.69 g / 4.61 g) was mixed with 32.0 parts by mass to obtain an adhesive layer composition.
This composition was applied to a release film (trade name: E7007, manufactured by Toyobo Co., Ltd., thickness: 38 μm), dried, and bonded to the surface of the optical functional layer.
In addition, about this contact bonding layer, it was 1.490 when the refractive index of 589 nm was measured using multiwavelength Abbe refractometer DR-M4 (made by Atago Co., Ltd.). Further, the storage elastic modulus of this adhesive layer was 0.22 MPa.

  In Test Example 2, a daylighting panel including a daylighting sheet was produced. FIG. 11 and Table 1 show the shape of the light deflection layer in Test Example 2, respectively. As can be seen from the above, in Test Example 2, the upper side of the light deflection unit was configured with a side that was a straight line in cross section.

In Test Example 3, a daylighting panel of an example of θ _U1 <θ _U2 was produced. The shape of the light deflection layer in Test Example 3 is shown in FIG. 12 and Table 1, respectively. As can be seen from this, in Test Example 3, the upper side of the light deflection unit is configured with a polygonal side that is convex upward in cross section.

  In Reference Example 1, only a panel was used without using a daylighting sheet.

About the lighting panel of each example shown above, direct light and lighting efficiency were measured and evaluated. Details are as follows.
White light was projected at a predetermined angle θ _SH and θ _SL by a light source (metal halide fiber light source, IMH-250, Sigma Kogyo Co., Ltd.). The illuminance of the light source was adjusted to 500 lx using an illuminometer (T-1H, Konica Minolta Optics, Inc.).
A luminance meter (LS-110, Konica Minolta Optics Co., Ltd.) was installed before the light incident on the daylighting sheet and after the light incident, the respective luminances were measured, and the daylighting efficiency was calculated from the luminance ratio. The daylighting efficiency of Test Example 1 was marked with ◯, and if it was equivalent to this, it was marked with ◯, and if it was lower, it was marked with x.
On the other hand, in the evaluation of direct light, the glare was subjectively evaluated, and the level that felt that it was not dazzling was marked with ◎, the level that felt that it was not dazzled was marked with ○, and the level that felt that it was impossible to see directly was marked with ×.
Table 2 shows the results.

As can be seen from the results in Table 2, even in the test example 1, the elevation angle θ _SH when the solar altitude is high and the elevation angle θ _SL when the solar altitude is low can suppress direct light while having good lighting efficiency. It was. As described above, when θ _SH , light is totally reflected by two oblique sides having different inclination angles and emitted to the indoor side in order. On the other hand, during θ _SL, light is totally reflected by the inclination on the indoor side. This is considered to be due to emission to the indoor side.

In Test Example 2, direct light was able to be suppressed in both cases of θ _SH and θ _SL , but the lighting efficiency was lowered when θ _SH .

In Test Example 3, the upper part of the light deflector is a polygonal line, but the inclination relationship is not appropriate, so that the lighting efficiency has been reduced at θ _SH .

DESCRIPTION OF SYMBOLS 1 Building 10 Daylighting device 11 Frame 12 Daylighting panel 13 Panel 20 Daylighting sheet 21 Hard coat layer 22 Base material layer 23 Light deflection layer 24 Light transmission part 25 Light deflection part 26 Adhesion layer

The invention according to claim 1 is a daylighting sheet in the form of a sheet disposed in a building opening so that the sheet surface is vertical, a sheet-like base material layer having translucency, and a base material layer And a light deflection layer that deflects light, and the light deflection layer includes a plurality of light transmission portions that transmit light arranged side by side along one surface of the base material layer, and a plurality of light transmission layers. And a light deflector filled with an ultraviolet curable resin composition having a refractive index lower than that of the light transmissive part, and the light deflection of the part where the light transmissive part is disposed. The front and back surfaces of the layers are formed in parallel, and the lighting sheet is arranged in the opening of the building, and the light deflection unit has a plurality of straight lines on the upper side of the lighting sheet in the thickness direction cross section. Is formed in a continuous polygonal line or curved shape, and the upper side is formed so as to protrude downward. , Is downwardly convex in the the upper sides, the inclination angle with respect to the horizontal plane in the inner chamber outside of the upper sides is formed to be larger than the inclination angle with respect to the horizontal plane at the interior side, of the upper side The side on the lower side opposite to the side is linear, and is 0 ° or more and 30 ° or less with respect to the sheet surface normal of the daylighting sheet, the upper side and the lower side The distance between the light transmitting portion and the light transmitting portion is reduced between the light transmitting portion and the light receiving portion among the sides formed between the side on the upper side and the side on the lower side. It is a daylighting sheet in which a recess is provided on the side that becomes the opening.

The invention according to claim 2 is the daylighting sheet according to claim 1, wherein the inclination angle on the outdoor side of the upper side is 0 ° or more and 23.1 ° or less, and the inclination angle on the indoor side is 0 ° or more. It is 1.7 degrees or less.

Claims (4)

It is a daylighting sheet that is in the form of a sheet placed in the building opening so that the sheet surface is vertical,
A sheet-like base material layer having translucency;
A light deflection layer formed on one surface of the base material layer for deflecting light,
The light deflection layer is
A light transmitting portion that transmits light arranged in a plurality along one surface of the base material layer;
A light deflecting portion disposed between the plurality of light transmitting portions and filled with a composition of an ultraviolet curable resin having a refractive index lower than that of the light transmitting portion, and
The front and back surfaces of the light deflection layer at the part where the light transmission part is disposed are formed in parallel,
In the posture in which the daylighting sheet is arranged in the opening of the building, the light deflection unit has a sectional line in the thickness direction of the daylighting sheet, and the upper side is a polygonal line in which a plurality of straight lines are continuous, or a curved shape The side on the upper side is formed to be convex downward,
The side on the lower side opposite to the side on the upper side is linear, and is 0 ° or more and 30 ° or less with respect to the sheet surface normal of the daylighting sheet,
The angle formed with respect to the sheet surface normal at the light emission side end of the side that becomes the upper side is smaller than the angle formed with respect to the sheet surface normal that becomes the lower part,
The daylighting sheet | seat in which the recessed part is provided in the edge | side of the side used as the opening between the said light transmissive parts among the sides | sides formed between the edge | side of the said upper side, and the edge | side of the said lower side.   The downward convexity on the side that becomes the upper side is formed such that an inclination angle with respect to the horizontal plane on the outdoor side of the side that becomes the upper side is larger than an inclination angle with respect to the horizontal plane on the indoor side. The daylighting sheet described in 1. A plate-like panel having translucency;
The daylighting sheet according to claim 1 or 2, which is attached to one surface of the panel;
And a frame arranged to surround at least the periphery of the panel.   The building in which the lighting device of Claim 3 was installed in the opening part formed in the wall.

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