JP2016024271A - Lighting film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve lighting efficiency with a simple structure.SOLUTION: A lighting film 1 changes propagation directions of light incident from one surface side of the film to exit, and includes a plurality of louvers 13 formed as spaced along the one surface of the film, and a base part 12 disposed around the plurality of louvers. Each of the plurality of louvers has a plurality of reflection faces 14a, 14b having different inclination angles with respect to the normal direction of the one surface. When the lighting film is disposed with the film surfaces along a vertical direction, an angle of the reflection face closest to the one surface of the film in the plurality of reflection surfaces, with respect to the normal direction of the one surface of the film, is larger than those of other reflection faces, where an angle from the normal direction of the one surface directing the exit side to a downward direction is set to be a positive angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a daylighting film that emits light by changing the traveling direction of incident light.

  Light control sheet that improves daylighting efficiency by deflecting outside light incident on the window toward the indoor ceiling as part of efforts to reduce carbon dioxide emissions and reduce power consumption by reducing the intensity of indoor lighting Etc. have been proposed. Here, the daylighting efficiency refers to the ratio of light traveling upward from the horizontal direction with respect to incident light.

  For example, Patent Documents 1 and 2 disclose optical elements that improve the daylighting efficiency by arranging a plurality of reflecting surfaces apart from each other along the incident surface of external light. Patent Documents 1 and 2 also disclose examples in which the inclination angles of a plurality of reflecting surfaces are changed.

JP 2011-227120 A JP 2012-38626 A

  As shown in Patent Documents 1 and 2, when a plurality of reflecting surfaces are arranged apart from each other, the light reflected by each reflecting surface hits the back side of the reflecting surface arranged adjacent to the upper side and is reflected again. There is a possibility that light may travel downward. In this case, the lighting efficiency cannot be increased.

  In order to prevent the light reflected by one reflecting surface from being incident on the reflecting surface arranged adjacent to the upper side, the pitch of the reflecting surfaces must be increased or the length of the reflecting surfaces in the layer direction must be shortened. Don't be. However, if the pitch of the reflecting surfaces is simply increased or the length in the layer direction is shortened, the proportion of light that is not incident on the reflecting surfaces also increases, making it impossible to improve the daylighting efficiency.

  This invention is made | formed in view of the subject mentioned above, The objective is to provide the lighting film which can improve the lighting efficiency with a simple structure.

In order to solve the above problems, in one embodiment of the present invention,
In the daylighting film that emits by changing the traveling direction of the light incident from one side,
A plurality of louver portions formed apart from each other along the one surface;
A base portion provided around the plurality of louver portions,
Each of the plurality of louver portions has a plurality of reflection surfaces with different inclination angles with respect to the normal direction of the one surface,
When the film surface of the daylighting film is arranged in the top-to-bottom direction, the angle to be made from the normal direction toward the emission side of the one surface to the direction of the ground side is positive,
Of the plurality of reflecting surfaces, the reflecting surface arranged at the position closest to the one surface has a larger angle with respect to the normal direction of the one surface than the remaining reflecting surfaces.

  When the film surface of the said daylighting film is arrange | positioned in the top-and-bottom direction, these reflective surfaces may be arrange | positioned so that it may become convex shape in the direction of the ground.

The base portion may have a plurality of grooves formed apart from each other along the one surface,
The plurality of louver portions may be provided in the corresponding groove.

  The reflective member may be a metal material deposited in the corresponding groove of the base portion.

  Another louver disposed adjacent to above the louver part having the reflection surface after the light incident on the reflection surface disposed at a position closest to the one surface is reflected by the reflection surface An angle with respect to the normal direction of the one surface of the reflective surface arranged closest to the one surface so as to pass through the light control layer without hitting the portion, the one of the plurality of louver portions At least one of the pitch in the surface direction and the length in the normal direction of the one surface may be adjusted.

  Of the plurality of reflection surfaces, the reflection surface farthest from the one surface may be substantially parallel to the normal direction of the one surface.

The reflective member is
A first reflective surface disposed proximate to the one surface;
A second reflective surface that is continuous with the first reflective surface and is disposed at a position farther from the one surface than the first reflective surface;
The first reflective surface may be more inclined with respect to the normal direction of the one surface than the second reflective surface.

  The first reflective surface may be inclined with respect to the second reflective surface at an angle of 4 degrees or more and less than 10 degrees.

  The thickness of the reflective member may be uniform.

  According to the present invention, it is possible to improve daylighting efficiency with a simple structure.

The figure which shows the cross-section of the lighting film 1 by one Embodiment of this invention. Sectional drawing which shows the structure of the louver part 13 in detail. (A) is an optical path diagram when sunlight having a solar altitude of 60 ° is incident on the daylighting film 1 having the louver part 13 of FIG. 2, and (b) is when sunlight having a solar altitude of 20 ° is incident. Optical path diagram. The figure which digitized the lighting efficiency at the time of changing the inclination-angle of the louver part 13 in three ways by simulation. Incident sunlight with a solar altitude of 20-60 ° is made by changing the inclination angle of the first reflecting surface 14a and the second reflecting surface 14b of the louver 13 within a range of 0-10 ° with respect to the normal direction of the incident surface 3a. The figure which shows the average lighting efficiency at the time of making it. The figure which shows an example of the cross-sectional structure of the laminated glass. The figure explaining the manufacturing process of the daylighting film.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale and the vertical / horizontal dimensional ratio are appropriately changed and exaggerated.

  In addition, as used in this specification, the shape and geometric conditions and the degree thereof are specified, for example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

  Further, in the present specification, terms such as “sheet”, “film”, and “plate” are not distinguished from each other only based on the difference in names. Therefore, for example, a “sheet” is a concept including a member that can also be called a film or a plate. As a specific example, the “light control sheet” includes members called “light control film”, “light control plate”, and the like.

  Further, in this specification, the “sheet surface (film surface, plate surface, panel surface)” is the plane of the target sheet-like member when the target sheet-like member is viewed as a whole and globally. A surface that matches the direction. Furthermore, in this specification, the “normal direction” used for a sheet-like (film-like, plate-like, panel-like) member refers to a normal direction to the sheet surface of the member.

  FIG. 1 is a view showing a cross-sectional structure of a daylighting film 1 according to an embodiment of the present invention. The daylighting film 1 of FIG. 1 includes a light control layer 3 disposed on the base material layer 2, an adhesive layer 4 disposed on the light control layer 3, and a protection disposed under the base material layer 2. And a film 5. The daylighting film 1 of FIG. 1 can be laminated on a daylighting tool 6 such as a window via an adhesive layer 4. Or the lighting film 1 by this embodiment may be integrally formed in the inside of the lighting tools 6, such as a window.

  If the adhesive layer 4 is left exposed, the daylighting film 1 adheres to an unintentional object. Therefore, before the daylighting film 1 is adhered to the daylighting tool 6 such as a window, it is not shown on the adhesive layer 4. A release film is often attached. The release film is peeled off before adhering the daylighting film 1 to the daylighting tool 6. The protective film 5 is peeled off after the daylighting film 1 is bonded to the daylighting tool 6. Hereinafter, each of the release film and the protective film 5 may be simply referred to as a “layer”.

  The light control layer 3 in FIG. 1 has a base portion 12 having a plurality of grooves 11 that are spaced apart along one surface 3 a, and a refractive index different from that of the base portion 12 and is disposed in the plurality of grooves 11. And a plurality of louver portions 13.

  Each of the plurality of louver portions 13 is a reflecting member 14 having a plurality of reflecting surfaces 14a and 14b having different inclination angles with respect to the normal direction of the incident surface 3a. These reflective surfaces are provided on the surface facing the top side of the louver portion 13 when the film surface of the daylighting film 1 of FIG. The thickness of the reflecting member 14, that is, the width in the direction along the incident surface 3 a of the reflecting member 14 suffices as long as the reflecting surfaces 14 a and 14 b can exhibit the reflecting function.

  Of the plurality of reflecting surfaces 14a, 14b of the reflecting member 14, the reflecting surface arranged at the position closest to the incident surface 3a has a larger angle with respect to the normal direction of the incident surface 3a than the remaining reflecting surfaces. . That is, the louver portion 13 has a plurality of reflecting surfaces 14a and 14b arranged so as to be convex in the ground (downward) direction when the film surface of the daylighting film 1 is arranged in the vertical direction. In the present specification, when the film surface of the daylighting film 1 is arranged in the vertical direction, the angle formed from the normal direction toward the emission side of the one surface 3a to the direction of the ground side is positive.

  Although FIG. 1 shows an example in which the reflecting member 14 has two reflecting surfaces, that is, a first reflecting surface 14a and a second reflecting surface 14b connected to the first reflecting surface 14a, three or more reflecting surfaces are provided. You may have. In this case, the three or more reflecting surfaces have different inclination angles with respect to the normal direction of the incident surface 3a. More specifically, the inclination angle decreases stepwise from the side closer to the incident surface 3a to the side farther from the side.

  In FIG. 1, the reflecting surface 14 b disposed at the farthest position from the incident surface 3 a among the plurality of reflecting surfaces 14 a and 14 b of the reflecting member 14 is disposed substantially parallel to the normal direction of the incident surface 3 a. Although an example is shown, the reflecting surface 14b may be disposed slightly inclined with respect to the normal direction of the incident surface 3a. However, as will be described later, when the reflecting surface 14b disposed at the farthest position from the incident surface 3a is not parallel to the normal direction of the incident surface 3a, incident light from a low angle passes between the louver portions 13. Since the frequency of slipping through increases, ideally, the reflecting surface arranged at the farthest position should be arranged parallel to the normal direction of the incident surface 3a.

  The reflection member 14 is formed by vapor-depositing a metal material having a high reflectance such as aluminum or silver in the groove portion of the base portion 12, and the thickness of the reflection member 14 is substantially uniform over the entire length. As described above, since the thickness of the reflecting member 14 can be reduced to such a degree that each reflecting surface can exhibit the reflecting function, the visibility when the opposite side is viewed through the daylighting film 1 is improved. For example, if the louver part 13 is formed of a resin material having a refractive index different from that of the base part 12 and the cross-sectional structure of the louver part 13 is a trapezoid or a triangle, it is blurred when the opposite side is viewed through the daylighting film 1. Are often visually recognized and give the viewer a sense of incongruity. However, when the louver part 13 is configured with a sufficiently thin reflecting member 14 as in the present embodiment, the visibility almost the same as that of the daylighting film 1 without the louver part 13 can be obtained. There is no risk of discomfort.

  FIG. 2 is a cross-sectional view showing the structure of the louver portion 13 in more detail. The louver part 13 in FIG. 2 has a first reflecting surface 14a and a second reflecting surface 14b having different inclination angles with respect to the normal direction of the incident surface 3a. FIG. 2 shows an example in which the difference in inclination angle between the first reflecting surface 14a and the second reflecting surface 14b is set to 8 °. More specifically, the first reflecting surface 14a of FIG. 2 has an inclination angle of 8 ° with respect to the normal direction of the incident surface 3a, and the second reflecting surface 14b has an inclination angle of 0 ° with respect to the normal direction of the incident surface 3a. It is.

  In FIG. 2, the total length in the normal direction of the first reflecting surface 14a of the louver portion 13 is 200 μm, the length of the first surface of the first reflecting surface 14a in the normal direction is 75 μm, and the second reflecting surface 14b The length of one surface in the normal direction is 125 μm, and the pitch of the louver portion 13 in the direction of the incident surface 3a is 80 μm.

  Note that FIG. 2 is an example, and the structure and pitch of the louver portion 13 are not limited to those illustrated. For example, taking into account the solar altitude throughout the year in Japan, the difference in inclination angle between the first reflecting surface 14a and the second reflecting surface 14b may be set to 4 ° or more and less than 10 °. Moreover, the full length of the louver part 13 is set to the range of 100-500 micrometers, for example, and a pitch is set to the range of 50 micrometers-200 micrometers, for example.

  FIG. 3A is an optical path diagram when sunlight having a solar altitude of 60 ° is incident on the daylighting film 1 having the louver part 13 of FIG. 2, and FIG. It is an optical path figure at the time of entering. 3 (a) shows the light path of sunlight from the solar altitude in summer, and FIG. 3 (b) shows the light path of sunlight from the solar altitude in winter. These figures were obtained by simulation. It is.

  As can be seen from FIG. 3A and FIG. 3B, the higher the solar altitude, the larger the incident angle with respect to the normal direction of the incident surface 3a, and the sunlight is on the second reflecting surface 14b side of the louver part 13. Rather, it is more incident on the first reflecting surface 14a side. Sunlight incident on the first reflecting surface 14a is reflected by the first reflecting surface 14a and travels obliquely upward, as indicated by the arrow line a1 in FIG. An arrow line a2 in FIG. 3A indicates the traveling direction of sunlight when the first reflecting surface 14a is parallel to the normal direction of the incident surface 3a. When the first reflecting surface 14a is parallel to the normal direction of the incident surface 3a, the light reflected by the first reflecting surface 14a travels upward at a steeper angle and is disposed adjacent to the upper side. The possibility of hitting the louver portion 13 is increased. The light that hits the louver part 13 disposed adjacent to the upper side is reflected by the louver part 13 and travels obliquely downward, so that it is not used for daylighting, which causes a reduction in daylighting efficiency.

  When the solar altitude is 60 ° and the refractive index of the base portion 12 of the light control layer 3 is 1.55, the traveling direction of sunlight incident on the incident surface 3a of the light control layer 3 is as follows according to Snell's law: (1).

  sin 60 ° / sin θ = 1.55 / 1 (1)

  In the equation (1), θ is an angle with respect to the normal direction of the light incident surface 3 a inside the light control layer 3. When equation (1) is solved for θ, θ = 34 °.

  Assuming that the first reflecting surface 14a of the louver part 13 is inclined by 8 ° with respect to the normal direction of the incident surface 3a, the traveling direction angle of the light reflected by the first reflecting surface 14a is the modulus of the incident surface 3a. With respect to the line direction, the angle is 18 ° as calculated by the following equation (2). However, regarding the reflected light, the case where the light travels in the upward direction in the figure from the normal direction of the incident surface 3a is positive.

  34 ° -8 ° -8 ° = 18 ° (2)

  The traveling direction angle of the light reflected from the first reflecting surface 14a when the first reflecting surface 14a is not inclined is 34 °, and the light travels at an angle 16 ° lower than this case. . For this reason, when the 1st reflective surface 14a inclines 8 degrees with respect to the normal line direction of the entrance plane 3a, most of the light reflected by the 1st reflective surface 14a is arrange | positioned adjacently upwards. The light control layer 3 passes obliquely upward without hitting the louvered portion 13.

  In this manner, the light reflected by the first reflecting surface 14a is advanced obliquely upward at a lower angle by tilting the first reflecting surface 14a clockwise by 8 ° with respect to the normal direction of the incident surface 3a. The possibility that this light hits the louver part 13 disposed adjacently upward is reduced. Therefore, the proportion of light passing through the daylighting film 1 can be increased, and the daylighting efficiency can be improved.

  On the other hand, when the solar altitude is 20 °, the traveling direction of sunlight inside the light control layer 3 is expressed by the following equation (3) from Snell's law.

  sin20 ° / sinθ = 1.55 / 1 (3)

  Solving this equation (3) for θ gives θ = 12.7 °.

  When the second reflecting surface 14b of the louver part 13 is arranged in parallel to the normal direction of the incident surface 3a, the light incident on the second reflecting surface 14b at θ = 12.7 ° is similarly an absolute angle of 12 Reflected diagonally upward at 7 °. Since the angle of 12.7 ° is a small angle, there is a possibility that the light reflected by the second reflecting surface 14b may pass obliquely upward through the daylighting film 1 without hitting the louver portion 13 adjacent to the upper side. Get higher.

  As indicated by an arrow line a3 in FIG. 3B, when the second reflecting surface 14b is arranged in parallel to the normal direction of the incident surface 3a, the incident surface 3a is changed to the second reflecting surface 14b. The incident light is sunlight with a low solar altitude, and when sunlight from such a low angle is incident on the second reflecting surface 14b, the reflected light of the second reflecting surface 14b is also the same. Proceed diagonally upward at a low angle. On the other hand, an arrow line a4 in FIG. 3B is an optical path of sunlight when the second reflecting surface 14b is arranged obliquely at the same inclination angle as the first reflecting surface 14a. In this case, sunlight from a low angle is not incident and reflected on the second reflecting surface 14b and passes through the daylighting film 1 obliquely downward. Therefore, it becomes impossible to improve the lighting efficiency. Therefore, it can be seen that the second reflecting surface 14b is preferably arranged at an angle that is parallel to the normal direction of the incident surface 3a or as close as possible to the parallel.

The limiting condition for preventing the light incident on and reflected from the first reflecting surface 14a of a certain louver part 13 from hitting the upper adjacent louver part 13 is that on the incident surface 3a side of the first reflecting surface 14a. This is a case where the light incident on and reflected by the end portion passes through the end portion on the exit surface side of the second reflecting surface 14b of the louver portion 13 adjacent to the upper side. In the present embodiment, this limit condition is referred to as condition 1. An arrow line a1 in FIG. 3A indicates an optical path of a light beam under the condition 1 (for example, a light beam having a solar altitude of 60 °). By adjusting at least one of the overall length and pitch of the louver part 13, it is possible to prevent the louver part 13 adjacent to the upper side from hitting this optical path.
The condition 1 will be described in more detail. As shown by a broken line in FIG. 3A, the first reflecting surface 14a on the side close to the incident surface 3a of the louver portion 13 has the same inclination angle as the second reflecting surface 14b. Assuming that the light reflected by the end of the first reflecting surface 14a on the incident surface 3a side hits the louver portion 13 adjacent to the upper side, the inclination angle of the first reflecting surface 14a is set to the second angle. If the reflection surface 14b is steep, it will not hit the louver portion 13 adjacent to the upper side. In order to satisfy Condition 1, as described above, it is possible to adjust the inclination angle of the first reflecting surface 14a in addition to adjusting the overall length and pitch of the louver portion 13.

  Here, the total length of the louver portion 13 is the length of the louver portion 13 extending along the normal direction of the incident surface 3a. The longer the overall length of the louver part 13, the more easily the light incident from the incident surface 3 a is incident on the louver part 13. On the other hand, the light splashed obliquely upward from the louver part 13 is adjacent to the upper side. The possibility of hitting another louver portion 13 is also increased. Therefore, the length of the louver portion 13 may not be too long or too short.

  Further, the pitch of the louver portions 13 is the interval between adjacent louver portions 13 in the direction along the incident surface 3a. As the pitch of the louver part 13 is narrower, the frequency with which the light incident from the incident surface 3a passes through between the louver parts 13 can be reduced. On the other hand, the light splashed upward from the louver part 13 upwards. The possibility of hitting another adjacent louver portion 13 is also increased. Therefore, the pitch of the louver part 13 may not be too narrow or too wide.

  Thus, it is necessary to adjust the length and pitch of the louver part 13 so that the light beam under the above-described condition 1 can be slanted upward.

  On the other hand, the lower the solar altitude, the lower the incident angle with respect to the normal direction of the incident surface 3a, and more sunlight enters the louver part 13 on the second reflecting surface 14b side. Sunlight incident on the second reflecting surface 14b is reflected and travels obliquely upward. Since sunlight is incident on the second reflecting surface 14b when the angle is low, the light reflected by the second reflecting surface 14b also travels obliquely upward at a low angle and does not hit the louver portion 13 adjacent to the upper side. .

The limiting condition in which the light incident and reflected on the second reflecting surface 14b of a certain louver part 13 travels obliquely upward is when the light is incident on the end of the second reflecting surface 14b on the emission side. In the present embodiment, this limit condition is referred to as condition 2. An arrow line a3 in FIG. 3B indicates the optical path of the light beam under this condition 2. By adjusting the total length and pitch of the louver part 13, the incident light (for example, light at a solar altitude of 20 °) in the condition 2 can be surely jumped up obliquely.
The condition 2 will be described in more detail. As shown by a broken line in FIG. 3B, the second reflecting surface 14b far from the incident surface 3a of the louver portion 13 has the same inclination angle as the first reflecting surface 14a. Assuming that the light passing through between the louver portions 13 is reflected by the second reflecting surface 14 and travels obliquely upward when the inclination angle of the second reflecting surface 14b is made gentler than that of the first reflecting surface 14a. This is the case. In order to satisfy the condition 2, as described above, it is possible to adjust the inclination angle of the second reflecting surface 14 in addition to adjusting the overall length and pitch of the louver portion 13.

  FIG. 4 is a diagram in which the lighting efficiency when the inclination angle of the louver portion 13 is changed in three ways is quantified by simulation. FIG. 4 shows (a) when both the first reflecting surface 14a and the second reflecting surface 14b are arranged in parallel to the normal direction of the incident surface 3a. (B) As in FIG. 2, the first reflecting surface 14a and the second reflecting surface 14b. When the reflecting surface 14b is inclined by 8 ° relative to each other, (c) both the first reflecting surface 14a and the second reflecting surface 14b are inclined by 8 ° from the normal direction of the incident surface 3a, and the lighting efficiency Is a numerical value. More specifically, in FIG. 4, for each of (a) to (c), the lighting efficiency when the solar altitude is changed in increments of 10 ° from 20 ° to 50 ° is shown numerically, and the solar altitude is 20 A value obtained by averaging the values of the daylighting efficiency from 0 ° to 50 ° is also shown.

  As can be seen from FIG. 4, the average value of the daylighting efficiency is maximized in the case (b) of the present embodiment. Therefore, also from the result of FIG. 4, the second reflecting surface 14b is arranged in parallel to the normal direction of the incident surface 3a and the first reflecting surface 14a is inclined by 8 ° as in the present embodiment. This is desirable for improving the daylighting efficiency.

  FIG. 5 shows a sun with an altitude of 20 to 60 ° by changing the inclination angle of the first reflecting surface 14a and the second reflecting surface 14b of the louver portion 13 in the range of 0 to 10 ° with respect to the normal direction of the incident surface 3a. It is a figure which shows the average lighting efficiency at the time of making light enter. FIG. 5 shows the results obtained by simulation.

  In FIG. 5, the inclination angles of the first reflecting surface 14a and the second reflecting surface 14b are changed in four ways, respectively, and the average lighting efficiency of 4 × 4 = 16 louver portions 13 in total is shown. As can be seen from FIG. 5, the average daylighting efficiency is highest when the first reflecting surface 14a of the present embodiment is 8 ° and the second reflecting surface 14b is 0 °.

  Thus, also from the results of FIGS. 4 and 5, it can be seen that the louver portion 13 having the first reflecting surface 14a and the second reflecting surface 14b according to the present embodiment is desirable from the viewpoint of improving the daylighting efficiency.

(Structure of lighting tool 6)
The daylighting film 1 of FIG. 1 can be placed and sealed between, for example, laminated glass, in addition to being attached to a daylighting tool 6 such as a window. FIG. 6 is a diagram illustrating an example of a cross-sectional structure of the laminated glass 10. As shown in the figure, adhesive layers 4 are disposed on both surfaces of the daylighting film 1, and a transparent base material 9 such as glass is adhered from both surfaces via the adhesive layers 4.

  Further, the daylighting film 1 according to the present embodiment may be adhered to the surface of at least a part of the slats of the blind via the adhesive layer 4. Alternatively, the daylighting film 1 may be incorporated inside each slat. Furthermore, the daylighting film 1 according to the present embodiment may be bonded to the surface of the roll-up blind via the adhesive layer 4.

(Manufacturing method of the daylighting film 1)
Next, the constituent material and manufacturing process of the daylighting film 1 according to the present embodiment will be described. As the material of the base portion 12, for example, a material obtained by mixing and homogenizing a photocurable prepolymer, a reactive dilution monomer, a mold release agent, and a photopolymerization initiator is used. As the material of the base portion 12, a curable resin such as a thermosetting resin or an electron beam curable resin may be used instead of the ultraviolet curable resin.

  For example, a mold roll 21 is used to form the groove 11 which is the base of the reflecting surfaces 14a and 14b as shown in FIG. The surface of the mold roll 21 is cut with a cutting tool in accordance with the shape of the groove 11 to form a plurality of convex portions 22 corresponding to the shape of each groove 11 as shown in FIG.

  The composition of the base portion 12 is filled with the composition of the base portion 12 between the mold roll 21 on which the convex portions 22 are formed and a nip roll (not shown) and pressurized with both rolls, and irradiated with ultraviolet rays, for example, with a high-pressure mercury lamp. The object is cured to form the base portion 12 as shown in FIG. Thereafter, the base portion 12 is released from the mold roller by a peeling roller (not shown) to produce an intermediate member including the base portion 12 in which the plurality of grooves 11 are formed.

  Next, a metal material 23 having a high reflectance such as aluminum or silver is deposited inside the groove 11 by, for example, an oblique deposition method as shown in FIG. Next, as shown in FIG. 7D, the same resin material as that of the base portion 12 is used to fill the gaps in the grooves 11 to form the louver portion 13. At this time, as shown in FIG. 7E, the entire surface of the base portion 12 connected to the opening of the groove 11 is covered with a resin material, and the louver portion 13 is formed inside the surface of the base portion 12. Good.

  The light control layer 3 is completed on the base material layer 2 until the process of FIG. 7D or FIG. Next, the adhesive layer 4 is formed on the incident surface 3 a side of the light control layer 3.

  As a material of the base material layer 2, for example, a transparent film such as polyethylene terephthalate (PET) or polycarbonate (PC) is used. The thickness of the base material layer 2 is 5 to 200 μm, preferably 10 to 150 μm, and more preferably 50 to 100 μm. If the thickness of the base material layer 2 is less than 5 μm, wrinkles may occur during production, resulting in poor productivity. Conversely, if the thickness of the base material layer 2 is greater than 200 μm, the cost increases. There is a possibility that a defect such as loss of ionizing radiation occurs when ionizing radiation is irradiated through the base material layer 2 during curing.

  The composition of the adhesive layer 4 is, for example, one or more of a thermoplastic resin such as polyvinyl acetal resin, ethylene vinyl acetate copolymer resin, ethylene acrylic copolymer resin, polyurethane resin, and polyvinyl alcohol resin. It may be used by mixing with additives such as an antioxidant and an ultraviolet shielding agent, or may be formed by mixing an acrylic resin adhesive, a crosslinking agent, and a diluent. The composition of the adhesive layer 4 is formed into a sheet or a film and disposed between the daylighting film 1 and the transparent base material. After extruding air by applying pressure, it is integrated with the daylighting film 1 by heating. If it is liquid, it is applied to the release film and dried, and then attached to the daylighting film 1.

  Thus, in this embodiment, since the louver part 13 is composed of the reflecting member 14 having the plurality of reflecting surfaces 14a and 14b having different inclination angles, the side closer to the incident surface 3a when the solar altitude is high. The light reflected by the reflective surface can be made to travel obliquely upward so as not to hit the louver portion 13 disposed adjacent to the upper side, so that the daylighting efficiency in summer can be improved. Further, when the solar altitude is low, the light is reflected by the reflection surface far from the incident surface 3a, and is allowed to travel obliquely upward so as not to hit the louver portion 13 disposed adjacent to the upper side. This can improve the daylighting efficiency in winter. Thus, the louver unit 13 according to the present embodiment can improve the lighting efficiency regardless of the season. Therefore, the use frequency of an air conditioner or a lighting device can be reduced, and the amount of carbon dioxide emissions can also be reduced.

  Further, since the louver portion 13 according to the present embodiment is formed by only the thin reflecting member 14, the opposite side can be seen through the window as compared with the case where the louver portion 13 is formed of a resin material having a refractive index difference from the base portion 12. Visibility is improved, and the possibility of giving the viewer a sense of incongruity is reduced.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

    DESCRIPTION OF SYMBOLS 1 Daylight film, 2 Base material layer, 3 Light control layer, 3a One side (incident surface), 4 Adhesive layer, 5 Protective film, 6 Daylighting tool, 11 Groove, 12 Base part, 13 Louver part, 14 Reflecting member, 14a 1st reflective surface, 14b 2nd reflective surface, 21 Mold roll

Claims (9)

In the daylighting film that emits by changing the traveling direction of the light incident from one side,
A plurality of louver portions formed apart from each other along the one surface;
A base portion provided around the plurality of louver portions,
Each of the plurality of louver portions has a plurality of reflection surfaces with different inclination angles with respect to the normal direction of the one surface,
When the film surface of the daylighting film is arranged in the top-to-bottom direction, the angle to be made from the normal direction toward the emission side of the one surface to the direction of the ground side is positive,
Of the plurality of reflecting surfaces, the reflecting surface disposed at a position closest to the one surface has a larger angle with respect to the normal direction of the one surface than the remaining reflecting surfaces.   The daylighting film according to claim 1, wherein when the film surface of the daylighting film is arranged in the top-and-bottom direction, the plurality of reflecting surfaces are arranged so as to be convex in the direction of the ground. The base portion has a plurality of grooves formed separately along the one surface,
The daylighting film according to claim 1, wherein the plurality of louver portions are provided in the corresponding grooves.   The daylighting film according to claim 3, wherein the reflecting member is a metal material deposited in the groove corresponding to the base portion.   Another louver disposed adjacent to above the louver part having the reflection surface after the light incident on the reflection surface disposed at a position closest to the one surface is reflected by the reflection surface An angle with respect to the normal direction of the one surface of the reflective surface arranged closest to the one surface so as to pass through the light control layer without hitting the portion, the one of the plurality of louver portions The daylighting film according to any one of claims 1 to 4, wherein at least one of a pitch in a surface direction and a length in a normal direction of the one surface is adjusted.   The daylighting film according to any one of claims 1 to 5, wherein a reflective surface farthest from the one surface among the plurality of reflective surfaces is substantially parallel to a normal direction of the one surface. The reflective member is
A first reflective surface disposed proximate to the one surface;
A second reflective surface that is continuous with the first reflective surface and is disposed at a position farther from the one surface than the first reflective surface;
The daylighting film according to any one of claims 1 to 6, wherein the first reflecting surface is more inclined with respect to the normal direction of the one surface than the second reflecting surface.   The daylighting film according to claim 7, wherein the first reflection surface is inclined at an angle of 4 degrees or more and less than 10 degrees with respect to the second reflection surface.   The daylighting film according to claim 1, wherein the reflective member has a uniform thickness.

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