WO2013005745A1

WO2013005745A1 - Window glass

Info

Publication number: WO2013005745A1
Application number: PCT/JP2012/067003
Authority: WO
Inventors: 康宏池田; 寛坂本; 海田　由里子
Original assignee: 旭硝子株式会社
Priority date: 2011-07-05
Filing date: 2012-07-03
Publication date: 2013-01-10
Also published as: JP2014177354A

Abstract

Provided is window glass that can control the amount of transmittance of infrared rays in accordance with the angle of incidence of solar light, and can effectively use the light energy of the infrared rays that are not transmitted. The window glass (3) is equipped with: laminated glass (main window glass body (6)) in which two glass sheets (50) and a diffraction grating sheet (1) sandwiched therebetween are pasted together with an intermediate film (52) therebetween; and a solar cell (62) disposed at both the top side and bottom side of the laminated glass main window glass body (6). The diffraction grating sheet (1) has: a transparent resin layer (10) having a first primary surface and a second primary surface that are parallel to each other; and a diffraction grating (20) comprising a plurality of lattice lines (22) disposed parallel to each other and at a predetermined pitch. The lattice lines (22) comprise a thin film of a material having a different refractive index from that of the transparent resin layer (10). The lattice lines (22) preferably are embedded in the transparent resin layer (10) in a manner so as to have a lengthwise direction extending parallel to the first primary surface and the second primary surface of the transparent resin layer (10).

Description

Window glass

The present invention relates to a window glass having a diffraction grating and having a solar cell.

As a window glass of a building, a glass plate in which a diffraction grating is formed (see Patent Document 1), and a film in which a diffraction grating is formed between two glass plates (see Patent Document 2). Proposed. According to the window glass, the amount of transmitted infrared light can be controlled according to the season (the altitude of the sun, that is, the incident angle of sunlight). The rise can be suppressed, and in the winter, infrared rays of sunlight can be efficiently taken into the room to raise the room temperature.

That is, the angle at which the incident angle to the interface when the infrared ray of sunlight incident on the window glass is emitted from the window glass to the air in summer when the incident angle of sunlight is large is equal to or greater than the critical angle at the interface. The grid line spacing and the grid line surface inclination are set so that the sunlight incident on the window glass is not diffracted in the winter when the incident angle of sunlight is small. In the summer, the infrared rays of sunlight that are incident on the window glass and diffracted by the diffraction grating are totally reflected at the interface between the window glass and air, so that they are confined inside the window glass. On the other hand, in the winter when the incident angle of sunlight is small, sunlight incident on the window glass passes through the window glass without being diffracted by the diffraction grating.

International Publication No. 2006/134983 Japanese Unexamined Patent Application Publication No. 2008-126631

However, in the summer, infrared light trapped inside the window glass is gradually absorbed by the window glass as it undergoes total reflection at the interface between the glass plate and air. Therefore, the trapped infrared light energy cannot be used effectively and is wasted.

The present invention provides a window glass that can control the amount of infrared transmission according to the incident angle of sunlight and can effectively use the infrared light energy that has not been transmitted for solar cells.

The window glass of the present invention comprises a window glass body having a diffraction grating and a solar cell disposed on at least one side of the window glass body.
It is preferable that the window glass body has a diffraction grating sheet provided with a glass plate and the diffraction grating.
The diffraction grating sheet has a transparent resin layer having a first main surface and a second main surface parallel to each other, and a diffraction grating composed of a plurality of grating lines arranged in parallel to each other at a predetermined pitch. The lattice lines are made of a thin film made of a material having a refractive index different from that of the transparent resin layer, and the lattice lines have a length direction with respect to the first main surface and the second main surface of the transparent resin layer. It is preferably embedded in the transparent resin layer so as to extend in parallel.

The lattice line is formed so that the length direction extends parallel to the first main surface and the second main surface of the transparent resin layer, and the surface of the thin film has a gradient. It is preferably embedded in the layer.
The grid lines are preferably made of a dielectric thin film having a refractive index larger than that of the transparent resin layer. The refractive index of the dielectric thin film constituting the lattice line is preferably 0.0001 to 1.8 higher than the refractive index of the transparent resin layer.
The diffraction grating sheet preferably further includes a first transparent substrate in contact with the first main surface.
The window glass main body may be a laminated glass in which two glass plates and a diffraction grating sheet sandwiched therebetween are bonded via an intermediate film.
The window glass main body may be a multi-layer glass in which two glass plates are arranged at a predetermined interval and a diffraction grating sheet is adhered to the inner surface of at least one glass plate.
The window glass body may have a diffraction grating sheet attached to the surface of a glass plate.
It is preferable that the solar cell is arranged on a side parallel to the length direction of the grating line of the diffraction grating in the diffraction grating sheet among at least one side of the window glass body.

The window glass of the present invention can control the amount of infrared transmission according to the incident angle of sunlight, and can effectively use the infrared light energy that has not been transmitted for solar cells.

It is sectional drawing which shows 1st Embodiment of the window glass of this invention. It is sectional drawing which shows 2nd Embodiment of the window glass of this invention. It is sectional drawing which shows 3rd Embodiment of the window glass of this invention. It is sectional drawing which shows one Embodiment of a diffraction grating sheet | seat. It is a perspective view which shows the transparent resin layer in the diffraction grating sheet | seat of FIG. It is sectional drawing which shows other embodiment of a diffraction grating sheet | seat. It is sectional drawing which shows other embodiment of a diffraction grating sheet | seat. It is sectional drawing which shows other embodiment of a diffraction grating sheet | seat. It is the schematic which shows an example of the state of light refraction and diffraction in the transparent resin layer of a window glass main body. It is the schematic which shows the other example of the state of light refraction and diffraction in the transparent resin layer of a window glass main body. It is a figure which shows the mode of permeation | transmission of the sunlight in the summer in the window glass of this invention. It is a figure which shows the mode of permeation | transmission of sunlight in the winter in the window glass of this invention. It is sectional drawing explaining the process (a) in the manufacturing method of a diffraction grating sheet | seat. It is a perspective view explaining the process (b) in the manufacturing method of a diffraction grating sheet | seat. It is sectional drawing explaining the process (c) in the manufacturing method of a diffraction grating sheet | seat. It is a graph which shows the spectral sensitivity characteristic (relationship between a wavelength and quantum efficiency) of the single crystal silicon type solar cell element used in the example. It is a graph which shows the spectrum of the light confined inside a window glass and radiate | emitted from the upper side and lower side of a window glass main body to the solar cell side.

The side of the window glass body in the present invention refers to a line segment that forms a polygon of the window glass body when the window glass body is viewed from the front, that is, a side surface of the window glass body.
The upper side of the window glass main body in the present invention refers to the uppermost side when the window glass is installed on an object such as a building or a vehicle among a plurality of sides of the window glass main body.
The lower side of the window glass body in the present invention refers to a side located on the lowermost side when the window glass is installed on an object such as a building or a vehicle among a plurality of sides of the window glass body.
Transparent in the present invention means that visible light and infrared light are transmitted.
The refractive index in the present invention is a refractive index at a wavelength of 589 nm.
Each dimension of the diffraction grating sheet in the present invention is an average value obtained by measuring each dimension at three positions in a transmission electron microscope (TEM) image or an atomic force microscope (AFM) image of the cross section of the diffraction grating sheet. .

<Window glass>
The window glass of this invention comprises the window glass main body which has a diffraction grating, and the solar cell arrange | positioned at the at least 1 edge | side of a window glass main body. As the window glass of the present invention, it efficiently diffracts the infrared rays of sunlight in the south-medium direction in summer when the light energy per unit area is the maximum in one year, and further totally reflects it at the interface between the window glass and air. From the point which can be done, the thing by which a solar cell is arrange | positioned at at least one of the upper side and lower side of a window glass main body is preferable, and the thing by which a solar cell is arrange | positioned at both the upper side and lower side of a window glass main body is more preferable.

(Window glass body)
The shape of the window glass body may be a shape that allows solar cells to be arranged on at least one side, that is, a polygonal shape. For example, in the case of a building or the like, usually a quadrangle (square, rectangular, trapezoid, etc.) It is. Further, it may be curved glass, and the sides and corners may be curved.

As a window glass body, the following (A) can be used because it can efficiently diffract sunlight with a wavelength in the infrared band at a wide angle of incidence, compared with a glass plate having a regular diffraction grating formed on the surface. The window glass main body of (C) is preferable, and the window glass main body of (A) is more preferable because it can be easily manufactured in a relatively short time and can easily be enlarged.

(A) What has a diffraction grating sheet | seat mentioned later and a glass plate.
(B) A window glass body in which a plurality of lattice lines are formed by irradiating a glass plate with interference light of laser light to change the refractive index of the irradiated portion (Patent Document 1).
(C) A window glass body in which a diffraction grating film in which a plurality of grating lines are formed by irradiating a photopolymer film with interference light of a laser beam to change the refractive index of the irradiated portion is sandwiched between two glass plates ( Patent Document 2).

Examples of the window glass body (A) include the following (A-1) to (A-3).
(A-1) Laminated glass in which two glass plates and a diffraction grating sheet, which will be described later, sandwiched between them are bonded via an intermediate film (first embodiment).
(A-2) Multi-layer glass in which two glass plates are arranged at a predetermined interval, and a diffraction grating sheet described later is adhered to the inner surface of at least one glass plate (second embodiment).
(A-3) Sheet-bonded glass in which a later-described diffraction grating sheet is bonded to the surface of a glass plate (third embodiment).

(Solar cell)
The solar cell may be any size as long as it can be disposed on at least one side of the window glass body and can receive light emitted from the side of the window glass body. From the viewpoint of ease of installation of the window glass, it is preferable that the length is approximately the same as or slightly smaller than the length of the side of the window glass body and the width is approximately equal to or slightly smaller than the thickness of the window glass body. Such a solar cell is disposed such that its light receiving surface (that is, a surface for taking in light) is on one side of the window glass body, for example, on the end surface side of the window glass body.

As the solar cell, a known solar cell can be mentioned. The types of solar cells include single crystal silicon type, polycrystalline silicon type, microcrystalline silicon type, amorphous silicon type, hybrid type, thin film silicon type, spherical silicon type, tandem type, multijunction type, compound type (GaAs type, CIS type, CIGS type, CZTS type, CdTe type, etc.), dye sensitized type, organic thin film type, quantum dot type and the like.

<Embodiment of window glass>
Examples of the window glass of the present invention having the window glass body (A) include the window glasses of the first to third embodiments.

(First embodiment)
FIG. 1 is a cross-sectional view showing a first embodiment of the window glass of the present invention. The window glass 3 is an upper side of a laminated glass (laminated glass type window glass main body 6) in which two glass plates 50 and a diffraction grating sheet 1 (described later) sandwiched therebetween are bonded via an intermediate film 52. And the solar cell 62 is arrange | positioned adjacent to a lower side (the left side surface and right side surface of a laminated glass in a figure). The upper side and the lower side of the laminated glass are sides parallel to the length direction of the grating line 22 of the diffraction grating 20 in the diffraction grating sheet 1. That is, the solar cell 62 is arranged on a side parallel to the length direction of the grating line 22 of the diffraction grating 20 in the diffraction grating sheet 1 of the laminated glass. In FIG. 1, solar cells 62 are disposed adjacent to the upper end face and the lower end face of the window glass body 6. The upper side and the lower side of the laminated glass need only be substantially parallel to the length direction of the lattice lines 22 and may not be completely parallel.

As the glass plate 50, a known glass plate for window glass may be used. The glass plate may be obtained by a float method or a downdraw method, or may be a template glass. Examples of the glass plate material include soda lime glass, borosilicate glass, aluminosilicate glass, and alkali-free glass.
As the intermediate film 52, an intermediate film (polyvinyl butyral film or the like) used for a known laminated glass may be used.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a second embodiment of the window glass of the present invention. The window glass 4 includes two glass plates 50, a frame-like spacer 56 disposed at the peripheral edge of the glass plate 50 so that a gap 54 is formed between the glass plates 50, the spacer 56, and the glass plate 50. A primary sealant 58 provided between the spacer 56, a secondary sealant 59 provided at the periphery of the spacer 56, and an inner surface of one glass plate 50, which is attached via an adhesive layer 60, which will be described later. In the double glazing (double glazing type window glass body 6) having the diffraction grating sheet 1, the spacers on the upper side and the lower side (left side and right side of the double glazing in the figure) among the four sides of the spacer 56. Reference numeral 56 denotes a solar cell 62. The upper side and the lower side of the multilayer glass are sides parallel to the length direction of the grating line 22 of the diffraction grating 20 in the diffraction grating sheet 1. That is, the solar cell 62 (spacer 56) is arranged on a side parallel to the length direction of the grating line 22 of the diffraction grating 20 in the diffraction grating sheet 1 of the multilayer glass. In FIG. 2, solar cells 62 (spacers 56) are arranged adjacent to the upper end face and the lower end face of the window glass body 6. The upper side and the lower side of the multilayer glass may be substantially parallel to the length direction of the lattice lines 22 and may not be completely parallel.

What is necessary is just to use the thing similar to 1st Embodiment as the glass plate 50. FIG.
As the spacer 56 (excluding the solar cell 62), as the primary sealing material 58 and the secondary sealing material 59, for example, the spacer, the primary sealing material, and the secondary sealing material described in Japanese Patent No. 4479690 may be used. .
As the pressure-sensitive adhesive layer 60, a known pressure-sensitive adhesive sheet or the like used when various films are stuck on a glass plate may be used.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a third embodiment of the window glass of the present invention. The window glass 5 is a sheet-attached glass (sheet-attached glass-type window glass body) having a glass plate 50 and a diffraction grating sheet 2 described later attached to the surface of the glass plate 50 via an adhesive layer 60. 6) A solar cell 62 is disposed adjacent to the upper side and the lower side (the left side surface and the right side surface of the sheet pasting glass in the drawing). The diffraction grating sheet 2 is attached to the surface of the glass plate 50 so that the hard coat layer 36 is the outermost layer. The upper side and the lower side of the sheet sticking glass are sides parallel to the length direction of the grating line 22 of the diffraction grating 20 in the diffraction grating sheet 1. That is, the solar cell 62 is arranged on a side parallel to the length direction of the grating line 22 of the diffraction grating 20 in the diffraction grating sheet 2 of the sheet-adhered glass. In FIG. 3, solar cells 62 are arranged adjacent to the upper end face and the lower end face of the window glass body 6. The upper side and the lower side of the sheet pasting glass only have to be substantially parallel to the length direction of the lattice lines 22 and may not be completely parallel.

What is necessary is just to use the thing similar to 1st Embodiment as the glass plate 50. FIG.
As the pressure-sensitive adhesive layer 60, the same layer as in the second embodiment may be used.

(Other forms)
The window glass of the present invention only needs to have a window glass body having a diffraction grating and a solar cell disposed on at least one side of the window glass body, and is not limited to those shown in FIGS. Not.

For example, the diffraction grating sheet provided with the diffraction grating does not have a transparent substrate (that is, does not have the first transparent substrate 32 and the second transparent substrate 34 as in FIG. 1), the transparent resin layer 10 and A diffraction grating sheet composed of only the diffraction grating 20 may be used.
Further, the diffraction grating sheet may be a diffraction grating sheet having either one of the first transparent substrate 32 and the second transparent substrate 34 on the surface of the transparent resin layer 10.
Moreover, the window glass main body which has the lamination type diffraction grating sheet | seat mentioned later may be sufficient.

<Embodiment of diffraction grating sheet>
Hereinafter, an embodiment of a diffraction grating sheet used for the window glass body of (A) will be described with reference to the drawings. The following figures are schematic diagrams, and an actual diffraction grating sheet does not have a theoretical and ideal shape as shown in the figure. For example, in an actual diffraction grating sheet, the shape of the grating line and the like is somewhat distorted.

FIG. 4 is a cross-sectional view showing an embodiment of a diffraction grating sheet, and FIG. 5 is a perspective view showing a transparent resin layer in the diffraction grating sheet. The diffraction grating sheet 1 includes a flat transparent resin layer 10 having a first main surface 18 and a second main surface 19 that are parallel to each other; and embedded in the transparent resin layer 10 in parallel with each other at a predetermined pitch Pp. A diffraction grating 20 comprising a plurality of grating lines 22; a first transparent substrate 32 in contact with the first main surface 18 of the transparent resin layer 10; a second contact in contact with the second main surface 19 of the transparent resin layer 10. And a transparent substrate 34.

(Transparent resin layer)
The transparent resin layer 10 has a first main surface 18 and a second main surface 19 that are parallel to each other. The first main surface 18 and the second main surface 19 may be formed substantially parallel to each other, and may not be formed completely parallel to each other.

Specifically, the transparent resin layer 10 has a concavo-convex surface in which a plurality of ridges 12 whose cross-sectional shape is a right triangle as shown in FIG. 4 are formed on the surface in parallel with each other at a predetermined pitch Pp. A first layer 14; a first layer 14; filled in a groove between the grid line 22 covering the first side surface of the ridge 12 and the ridge 12, and completely covering the top of the ridge 12 and the grid line 22. 2 is a laminate including two layers 16. The interface between the first layer 14 and the first transparent substrate 32 is the first main surface 18 of the transparent resin layer 10, and the interface between the second layer 16 and the second transparent substrate 34 is a transparent resin. This is the second major surface 19 of the layer 10.

The ridge 12 is a portion that rises from the flat portion of the first layer 14 and that rises in one direction. The ridge 12 may be integrated with the flat portion of the first layer 14 and may be made of the same material as the flat portion of the first layer 14, or may be made of a transparent resin different from the flat portion of the first layer 14. Good. The ridges 12 are preferably integral with the flat portion of the first layer 14 and made of the same material as the flat portion of the first layer 14.

The plurality of ridges 12 may be formed substantially parallel to each other, and may not be formed completely parallel. Moreover, although the thing of the shape extended in linear form is preferable, the thing of the shape extended in the shape of a curve or a broken line may be sufficient in the range which the adjacent protruding item | line 12 does not contact.

It is preferable that the shape of the cross-section orthogonal to the length direction of the ridges 12 is substantially constant over the length direction, and all of the cross-sectional shapes of the plurality of ridges 12 are also substantially constant. The cross-sectional shape of the ridge 12 is a shape in which the width gradually decreases from the bottom (the flat portion of the first layer 14) toward the top. Specific examples of the cross-sectional shape include a triangle and a trapezoid. The corners in the cross-sectional shape may be curved. Further, the side (side surface) in the cross-sectional shape may be curved or may be stepped. In addition, the cross-sectional shape of the protruding item | line 12 is not limited to these shapes, A rectangle etc. may be sufficient.

The top of the ridge 12 is a portion in which the highest portion of the cross-sectional shape is continuous in the length direction. The top of the ridge 12 may be a surface or a line. For example, when the cross-sectional shape is trapezoidal, the top portion forms a surface, and when the cross-sectional shape is triangular, the top portion forms a line. In the present invention, the surface other than the top of the ridge 12 is referred to as a side surface of the ridge 12.

The ridge 12 has a first side surface and a second side surface. Of the first side surface and the second side surface, the lattice line 22 is formed on at least a part of the first side surface. Of the first side surface and the second side surface, at least the first side surface preferably has a gradient with respect to the first main surface 18. As long as it has a gradient, the first side surface may be a flat surface, a curved surface, or a stepped shape. The second side surface may be perpendicular to the first main surface 18 and may have a slope.
In the above description, the example in which the first side surface of the ridge 12 is the right side surface of the ridge 12 and a thin film functioning as a grid line is formed on the first side surface has been described. The first side surface may be handled as the left side surface of the ridge, and the second side surface of the ridge may be handled as the right side surface of the ridge. In this case, a thin film functioning as a lattice line is formed on the left side surface opposite to the right side surface described in FIG. Hereinafter, the same applies to the description of the present specification.

The transparent resin layer 10 (the first layer 14 and the second layer 16 are also collectively referred to as the transparent resin layer 10) is a layer made of a transparent resin.
As the transparent resin, a photo-curing resin or a thermoplastic resin is preferable from the viewpoint that the ridges 12 can be formed by the imprint method described later and the lattice lines 22 are easily embedded in the transparent resin layer 10. A photo-curing resin is particularly preferable from the viewpoint that the ridges 12 can be formed by the above-mentioned method and that heat resistance and durability are excellent. As the photocurable resin, a photocurable resin obtained by photocuring a photocurable composition that can be photocured by photoradical polymerization is preferable from the viewpoint of productivity.

The refractive index of the transparent resin layer 10 (the first layer 14 and the second layer 16) is preferably 1.25 to 1.8, and more preferably 1.3 to 1.7. If the refractive index of the transparent resin layer 10 is within the above range, the transparent resin layer 10 and the first transparent substrate 32 are appropriately selected by appropriately selecting the materials of the first transparent substrate 32 and the second transparent substrate 34. Alternatively, the difference in refractive index between the transparent resin layer 10 and the second transparent substrate 34 can be easily reduced.

The difference (absolute value) in refractive index between the first layer 14 and the second layer 16 is preferably 0.1 or less, and more preferably 0.05 or less. If the difference in refractive index is 0.05 or less, stray light and loss due to reflection, diffraction, etc. at the interface between the first layer 14 and the second layer 16 can be suppressed. Moreover, if the refractive index of the 1st layer 14 and the 2nd layer 16 is the same, optical design will become easy.
From the viewpoint of reducing the difference in refractive index between the first layer 14 and the second layer 16, the material of the first layer 14 and the material of the second layer 16 are preferably substantially the same material. More preferably, they are the same material.

(Lattice line)
The diffraction grating 20 includes a plurality of grating lines 22 embedded in parallel with each other at a predetermined pitch Pp. In the present specification, the term “lattice line” includes a thin-film lattice line and a lattice line having a predetermined width. The plurality of grid lines 22 may be formed substantially parallel to each other, and may not be formed completely parallel. The lattice lines 22 are preferably linear, but may be curved or polygonal as long as the adjacent lattice lines 22 do not contact each other. Moreover, the end surface in the length direction of the lattice line 22 may be exposed from the side surface of the transparent resin layer 10.

The plurality of lattice lines 22 are formed so that the length direction of the transparent resin layer 10 extends in parallel with a predetermined interval with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10. The lattice lines 22 need only be formed substantially parallel to the length direction of the first main surface 18 and the second main surface 19 of the transparent resin layer 10, and are formed completely in parallel. It does not have to be.

The plurality of grid lines 22 are formed so that the length direction thereof extends in parallel to the upper side and the lower side of the window glass body 6. The lattice lines 22 may be formed so that the length direction thereof is substantially parallel to the upper side and the lower side of the window glass body 6, and may not be formed completely in parallel.

It is preferable that the cross-sectional shape of the lattice line 22 in the direction orthogonal to the length direction is substantially constant over the length direction, and the cross-sectional shape of all the lattice lines 22 is also substantially constant.

When the lattice lines 22 are formed on at least a part of the surface of the ridges 12, the lattice lines 22 are composed of thin films extending in the length direction of the ridges 12. The grid lines 22 preferably cover at least a part of the first side surface of the ridge 12, and more preferably completely cover the first side surface. At this time, the lattice line 22 may cover a part or all of the top of the ridge 12, or cover all of the top of the ridge 12 and a part of the second side surface of the ridge 12. Also good. The lattice line 22 may cover a part of the flat portion between the two adjacent ridges 12.

The lattice lines 22 are preferably formed so that the surfaces of the thin films constituting the lattice lines 22 have a gradient with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10. If the surface of the thin film has a gradient with respect to the first main surface 18 and the second main surface 19, the light diffracted by the diffraction grating is directed in the outdoor direction or toward the end of the transparent resin layer 10. Control of the emission direction such as emission becomes easy. The gradient angle φ _g of the surface (lattice plane) of the thin film constituting the lattice line 22 with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10 is the first main surface 18 of the transparent resin layer 10. It becomes the same as the angle φ _p (see FIG. 14) of the slope of the first side surface of the ridge 12 with respect to the surface 18 and the second main surface 19. The surface of the thin film may be a flat surface, a curved surface, or a step shape as long as it has a gradient.

The thin film which comprises the lattice line 22 with respect to the 1st main surface 18 and the 2nd main surface 19 of the pitch Pp of the lattice line 22, the height Hg of the lattice line 22, the thickness Dg of the lattice line 22, and the transparent resin layer 10 The surface gradient angle φ _{g and the} like may be appropriately set by, for example, a diffraction grating design method described later.

The pitch Pp of the grid lines 22 is the distance from the left end (or right end) of the cross section of the grid lines 22 to the left end (or right end) of the cross section of the grid lines 22 adjacent thereto, and the thickness of the grid lines 22 Dg is the maximum value of the thickness in the same direction as the width direction of the ridges 12 in the cross section perpendicular to the length direction of the grid lines 22, and the height Hg of the grid lines 22 is the length direction of the grid lines 22. It is the height in the same direction as the height direction of the ridge 12 in the cross section orthogonal to.

The lattice lines 22 are made of a thin film of a material having a refractive index different from that of the transparent resin layer 10 (hereinafter also referred to as a lattice line material).
Examples of the lattice line material include dielectrics (inorganic oxides, resins, etc.), metals, and the like. Examples of the inorganic oxide include silicon dioxide, aluminum oxide, titanium oxide, and zirconium dioxide (hereinafter referred to as zirconia). Examples of the resin include a photo-curing resin and a thermoplastic resin. Examples of the metal include simple metals, alloys, metals containing dopants or impurities, and the like. Specifically, aluminum, silver, chromium, magnesium, an aluminum alloy, a silver alloy, and the like can be given.

The lattice lines 22 are preferably made of a dielectric thin film having a higher refractive index than the transparent resin layer 10. When making the refractive index of the lattice line 22 (dielectric) smaller than the refractive index of the transparent resin layer 10 by making the refractive index of the lattice line 22 (dielectric) larger than the refractive index of the transparent resin layer 10 Compared to the above, it becomes easy to increase the refractive index difference and increase the diffraction efficiency. There are also more choices for dielectrics.

In order to improve the diffraction efficiency, the grating line material is preferably a material having a large refractive index difference from the transparent resin material 10, and since the refractive index difference from the resin can be increased and the diffraction efficiency can be increased, the dielectric material Of these thin film materials, titanium oxide and zirconia are preferable, and zirconia is particularly preferable. Further, although the diffraction efficiency is lower than that of titanium oxide and zirconia, silicon dioxide is also preferable from the viewpoint of high transmittance for visible light and infrared rays, easy formation of a thin film, and low cost.
The refractive index of the thin film constituting the lattice line 22 (that is, the lattice line material) is preferably 0.0001 to 1.8 higher than the refractive index of the transparent resin layer 10. Within this range, the diffraction efficiency is high and the wavelength dispersion of the transmittance hardly occurs.

(Transparent substrate)
The diffraction grating sheet 1 has transparent substrates (a first transparent substrate 32 and a second transparent substrate 34) made of a thermoplastic resin or the like on the surface of the transparent resin layer 10. The first transparent substrate and the second transparent substrate are, for example, (meth) acrylic resins such as polymethyl methacrylate, a copolymer of methyl methacrylate and other vinyl (meth) acrylate, a vinyl monomer such as styrene, and the like; Polycarbonate resins such as polycarbonate and diethylene glycol bisallyl carbonate (CR-39); (brominated) homopolymer or copolymer of bisphenol A type di (meth) acrylate, (brominated) bisphenol A mono (meth) acrylate Thermosetting (meth) acrylic resins such as polymers and copolymers of urethane-modified monomers; polyesters, especially polyethylene terephthalate, polyethylene naphthalate and unsaturated polyesters, acrylonitrile-styrene copolymers, polyvinyl chloride, Polyurethane, epoxy resins, polyarylate, polyether sulfone, polyether ketone, cycloolefin polymer (trade name: ARTON, ZEONOR) and the like are preferable. Moreover, the aramid resin etc. which considered heat resistance are mentioned. The first transparent substrate and the second transparent substrate may be film-like or plate-like, and both are referred to as transparent substrates.

The refractive index difference (absolute value) between the transparent substrate and the transparent resin layer 10 is preferably 0.1 or less, and more preferably 0.05 or less. If the difference in refractive index is 0.1 or less, light loss due to reflection occurring at the interface between the transparent resin layer 10 and the transparent substrate can be suppressed.

(Other forms)
The diffraction grating sheet of the present invention includes a transparent resin layer having a first main surface and a second main surface parallel to each other, and a diffraction grating composed of a plurality of grating lines arranged in parallel to each other at a predetermined pitch Pp. The grating line is made of a thin film made of a material having a refractive index different from that of the transparent resin layer, and the grating line is formed with respect to the first main surface and the second main surface of the transparent resin layer. As long as it is embedded in the transparent resin layer so that its length direction extends in parallel, it is not limited to those shown in FIGS.

For example, the surface of the dielectric thin film constituting the lattice line 22 may not have a gradient with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10, that is, the first It may be perpendicular to one major surface 18 and second major surface 19.
In addition, a diffraction grating sheet including only the transparent resin layer 10 and the diffraction grating 20 may be used without the transparent substrates (the first transparent substrate 32 and the second transparent substrate 34).
Moreover, the diffraction grating sheet | seat which has any one among the 1st transparent substrate 32 and the 2nd transparent substrate 34 on the surface of the transparent resin layer 10 may be sufficient. In the case where either one of the first transparent substrate 32 and the second transparent substrate 34 is included, the diffraction grating sheet having the first transparent substrate 32 on the surface of the transparent resin layer 10 is easy to manufacture the diffraction grating sheet. preferable.

Further, as shown in FIG. 6, the diffraction grating sheet 2 having a hard coat layer 36 on the surface of the second transparent substrate 34 (or the first transparent substrate 32) may be used.
Examples of the material of the hard coat layer 36 include a resin (such as a photo-curing resin) and an inorganic oxide (such as silicon dioxide).

Further, it may be a diffraction grating sheet in which a plurality of diffraction grating sheets 1 are laminated, or a diffraction grating sheet in which a plurality of transparent resin layers 10 in which diffraction gratings 20 are embedded are laminated. Under the present circumstances, the angle of the gradient of the surface of the thin film which comprises the lattice line 22 with respect to the 1st main surface 18 and the 2nd main surface 19 of the length direction of the lattice line 22 in each transparent resin layer 10 and the transparent resin layer 10 φ _g , the pitch Pp of the lattice lines 22, etc. may be the same for each transparent resin layer 10, may be different for some transparent resin layers 10, or may be different for each transparent resin layer 10. .

For example, as shown in FIG. 7, a diffraction grating 20a in which the length direction of the grating line 22 extends in the x direction and the surface of the thin film constituting the grating line 22 slopes in the −z direction as it goes in the + y direction is embedded. Transparent resin layer 10a; a transparent resin in which a diffraction grating 20b in which the length direction of the grating line 22 extends in the x direction and the surface of the thin film constituting the grating line 22 is inclined in the + z direction as it goes in the + y direction is embedded A transparent resin layer 10c in which a diffraction grating 20c in which the length direction of the grating line 22 extends in the z direction and the surface of the thin film constituting the grating line 22 slopes in the −x direction as it goes in the + y direction is embedded in the layer 10b; A transparent resin layer 10d in which a diffraction grating 20d in which the length direction of the grating line 22 extends in the z direction and the surface of the thin film constituting the grating line 22 is inclined in the + x direction as it goes in the + y direction is embedded. There may be a diffraction grating sheet with a transparent resin layer 10 which are stacked. According to the window glass having the diffraction grating sheet, the infrared rays of sunlight diffracted by the diffraction grating in any of the transparent resin layers are efficiently transmitted to the solar cell 62 regardless of the altitude and direction (morning, evening, and season) of the sun. Well incident. Moreover, even if the incident direction of sunlight changes when the traveling direction changes as in a vehicle (automobile or the like), any transparent resin is used regardless of the traveling direction of the vehicle (automobile or the like). The infrared rays of sunlight diffracted by the diffraction grating 20 in the layer efficiently enter the solar cell 62. In the window glass having the diffraction grating sheet, the solar cell 62 may be provided on four sides of the window glass.

Further, as shown in FIG. 8, the direction of the gradient of the surface of the thin film constituting the lattice line 22 with respect to the length direction of the lattice line 22 and the first main surface 18 and the second main surface 19 of the transparent resin layer 10. and the angle phi _g may be a diffraction grating sheet with a transparent resin layer 10e is embedded the same diffraction grating 20 and the transparent resin layer 10f has been transparent resin layer 10 laminated. According to the diffraction grating sheet, compared with the single transparent resin layer 10, the infrared diffraction efficiency of sunlight having a specific incident angle and wavelength desired to be diffracted can be further increased.

<Diffraction grating design method>
The thin film which comprises the lattice line 22 with respect to the 1st main surface 18 and the 2nd main surface 19 of the pitch Pp of the lattice line 22, the height Hg of the lattice line 22, the thickness Dg of the lattice line 22, and the transparent resin layer 10 The gradient angle φ _g of the surface of the light source includes the range of the infrared wavelength for which the amount of transmission is desired to be suppressed, the range of the incident angle of sunlight for which the amount of infrared transmission is desired to be suppressed, and the materials constituting the diffraction grating sheet (transparent resin layer 10 , The thin film of the lattice line 22, the refractive index of the first transparent substrate 32, the second transparent substrate 34, the hard coat layer 36, etc., and each material constituting the window glass (glass plate 50, intermediate film 52, adhesive layer) 60) and the like, and may be set as appropriate based on known optical knowledge (

Patent Documents

1, 2, etc.).

For example, the angle φ _g of the gradient of the surface of the thin film constituting the lattice lines 22 with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10 is as follows. An angle φ _n of the gradient of the surface of the thin film constituting the lattice line 22 with respect to the normal lines of the first main surface 18 and the second main surface 19 can be obtained and calculated from φ _g = 90−φ _n .
In addition, the pitch Pp of the grid line 22 which is the distance from the left end (or right end) of the cross section of the grid line 22 to the left end (or right end) of the cross section of the grid line 22 adjacent thereto is set as follows. It can be calculated by obtaining a lattice line interval d in the normal direction of the line 22.

(Case 1)
FIG. 9 shows the state of light refraction and diffraction in the transparent resin layer 10 of the window glass body 6 in which the surface of the thin film constituting the lattice line 22 is inclined toward the upper side (right side of the drawing) as it goes toward the sunlight incident surface. It is the schematic which shows an example. In addition, in the case of the window glass main body 6, in addition to the transparent resin layer 10, it has the

transparent substrates

32 and 34, the intermediate film 52, and the glass plate 50, but between the air and the transparent resin layer 10 by Snell's law described later. Even if a material other than the transparent resin layer 10 is present, the angle of refraction of sunlight finally incident on the transparent resin layer 10 is the same as when no material other than the transparent resin layer 10 is present. Therefore, for the sake of simplification, using a model in which sunlight is directly incident on the transparent resin layer 10 from the air, lattice lines with respect to the normal lines of the first main surface 18 and the second main surface 19 of the transparent resin layer 10 are used. A method of obtaining the gradient angle φ _n and the lattice line spacing d of the surface of the thin film constituting the film 22 will be described. In order to avoid the complexity of the drawing, only two grid lines 22 in the transparent resin layer 10 are shown, and the other grid lines 22 are omitted.

Sunlight that has entered the transparent resin layer 10 (refractive index n ₁ ) from the air (refractive index n ₀ ) at an incident angle θ ₀ is refracted at the refractive angle θ ₁ at the interface according to Snell's law, which will be described later.
When the Bragg condition described later is satisfied, a part of the refracted sunlight (infrared rays) is a thin film constituting the lattice line 22 with respect to the normal lines of the first main surface 18 and the second main surface 19 of the transparent resin layer 10. the grid lines 22 is the slope of the surface of the angle phi _n of, at an incident angle phi _n - [theta] _1, diffracted (reflected) by the diffraction angle phi _n - [theta] _1. On the other hand, when the Bragg condition is not satisfied, the refracted sunlight is emitted from the transparent resin layer 10 to the air without being diffracted by the lattice line 22.
The diffracted infrared light is incident on the interface between the transparent resin layer 10 and air at an incident angle β. When the incident angle β is greater than or equal to the critical angle γ at the interface (β−γ ≧ 0), the infrared rays are totally reflected at the interface and confined inside the window glass 3, and are reflected on the lower side (left side of the drawing). It is guided to a solar cell (not shown). On the other hand, when the incident angle β is less than the critical angle γ at the interface (β−γ <0), infrared rays are refracted at the interface and emitted from the transparent resin layer 10 to the air.

Here, the incident angle β is expressed by the following equation (1).
β = 2φ _n −θ ₁ (1)
Further, the refraction angle θ ₁ is represented by the following expression (3) from Snell's law of the following expression (2).
n ₀ sin θ ₀ = n ₁ sin θ ₁ (2)
θ ₁ = arcsin {(n ₀ / n ₁ ) sin θ ₀ } (3)
The critical angle γ is expressed by the following formula (4).
γ = arcsin {n ₀ / n ₁ } (4)
Substituting Equations (1), (3), and (4) into β-γ yields Equation (5) below.
β-γ = 2φ _n -arcsin {(n ₀ / n ₁ ) sin θ ₀ } -arcsin {n ₀ / n ₁ } (5)
The incident angle theta ₀ of infrared want diffracted formula (5) _(e.g., 60 °), the refractive index n ₀ of _air, enter the refractive index n ₁ of the transparent resin layer 10, such as the right-hand side is 0 or more, An angle φ _n of the surface gradient of the thin film constituting the lattice line 22 with respect to the normal lines of the first main surface 18 and the second main surface 19 of the transparent resin layer 10 is obtained.

The lattice line interval d causing diffraction is expressed by the Bragg condition of the following equation (6).
d = λ / {2n ₁ sin (φ _n −θ ₁ )} (6)
Infrared wavelength λ (for example, 800 nm), refraction angle θ ₁ (formula (3)) to be diffracted into formula (6), normal line of first main surface 18 and second main surface 19 of transparent resin layer 10 Then, the gradient angle φ _n of the surface of the thin film constituting the lattice line 22 is input to obtain the lattice line interval d.

(Case 2)
FIG. 10 shows the state of light refraction and diffraction in the transparent resin layer 10 of the window glass body 6 in which the surface of the thin film constituting the lattice line 22 is inclined toward the lower side (left side of the drawing) as it goes toward the sunlight incident surface. It is the schematic which shows an example. As described above, for simplification, the method of the first main surface 18 and the second main surface 19 of the transparent resin layer 10 using a model in which sunlight directly enters the transparent resin layer 10 from the air. A method of obtaining the angle φ _n of the gradient of the surface of the thin film constituting the grid line 22 and the grid line spacing d with respect to the line will be described. In order to avoid the complexity of the drawing, only two grid lines 22 in the transparent resin layer 10 are shown, and the other grid lines 22 are omitted.

Sunlight that has entered the transparent resin layer 10 (refractive index n ₁ ) from the air (refractive index n ₀ ) at an incident angle θ ₀ is refracted at the refractive angle θ ₁ at the interface according to Snell's law.
When the Bragg condition is satisfied, a part of the refracted sunlight (infrared rays) is the surface of the thin film constituting the lattice line 22 with respect to the normal line of the first main surface 18 and the second main surface 19 of the transparent resin layer 10. the grid lines 22 is the angle of the gradient phi _n, at an incident angle φ _n + θ _1, diffracted (reflected) by the diffraction angle φ _n + θ _1. On the other hand, when the Bragg condition is not satisfied, the refracted sunlight is emitted from the transparent resin layer 10 to the air without being diffracted by the lattice line 22.
The diffracted infrared light is incident on the interface between the transparent resin layer 10 and air at an incident angle β. When the incident angle β is greater than or equal to the critical angle γ at the interface (β−γ ≧ 0), the infrared rays are totally reflected at the interface and confined inside the window glass 3, and are reflected on the upper side (right side of the drawing). It is guided to a solar cell (not shown). On the other hand, when the incident angle β is less than the critical angle γ at the interface (β−γ <0), infrared rays are refracted at the interface and emitted from the transparent resin layer 10 to the air.

Here, the incident angle β is expressed by the following equation (7).
β = 2φ _n + θ ₁ (7)
As in Case 1, substituting Equations (7), (3), and (4) into β-γ yields Equation (8) below.
β-γ = 2φ _n + arcsin {(n ₀ / n ₁ ) sin θ ₀ } -arcsin {n ₀ / n ₁ } (8)
The incident angle theta ₀ of infrared want diffracted formula (8) _(e.g., 60 °), the refractive index n ₀ of _air, enter the refractive index n ₁ of the transparent resin layer 10, such as the right-hand side is 0 or more, An angle φ _n of the surface gradient of the thin film constituting the lattice line 22 with respect to the normal lines of the first main surface 18 and the second main surface 19 of the transparent resin layer 10 is obtained.

The lattice line interval d causing diffraction is expressed by the Bragg condition of the following equation (9).
d = λ / {2n ₁ sin (φ _n + θ ₁ )} (9)
Infrared wavelength λ (for example, 800 nm), refraction angle θ ₁ (formula (3)) to be diffracted into formula (9), normal lines of first main surface 18 and second main surface 19 of transparent resin layer 10 Then, the gradient angle φ _n of the surface of the thin film constituting the lattice line 22 is input to obtain the lattice line interval d.

In case 1 and case 2, the first main surface 18 and the second main surface 19 of the transparent resin layer 10 obtained using the incident angle θ _{0 of the} infrared ray to be diffracted and the wavelength λ of the infrared ray to be diffracted. The angle φ _n of the gradient of the surface of the thin film constituting the lattice line 22 and the lattice line interval d with respect to the normal line are only one point each. However, in the actual diffraction grating, the gradient angle φ _n and the grating line of the surface of the thin film constituting the grating line 22 with respect to the normal lines of the first main surface 18 and the second main surface 19 of the transparent resin layer 10 Even if the distance d is fixed at one point, the range of incident angles having a certain width before and after the incident angle θ ₀ of infrared rays to be diffracted, and to some extent around the wavelength λ of infrared rays to be diffracted Infrared rays in the wavelength range having a width of 2 are totally reflected at the interface between the transparent resin layer 10 and air and confined in the inside of the window glass body 6, on the lower side (case 1) or the upper side (case 2). It is guided to a solar cell (not shown).
Further, in the actual window glass body 6 having the diffraction grating sheet 1, the light reflected again by the adjacent grating line 22, the window glass body 6 and the solar battery that have been guided to the lower side solar cell after being guided. There is a possibility that light other than the emission direction assumed in the above-described design may be generated, such as light that is reflected and returned from the interface. Therefore, in order to receive such light, it is preferable to place a solar cell also on the upper side of the window glass body 6 (that is, on both the lower side and the upper side).

By designing the diffraction grating 20 as described above, as shown in FIG. 11, in the summer when the altitude of the sun is high (sunlight incident angle θ ₀ is large), the sunlight that has entered the window glass body 6 Among them, a part of infrared rays having a long wavelength is diffracted by the diffraction grating 20, guided to the solar cell 62, and not taken into the room. On the other hand, as shown in FIG. 12, in the winter when the altitude of the sun is low (sunlight incident angle θ ₀ is small), the sunlight (visible light to infrared light) incident on the window glass body 6 is reflected by the diffraction grating 20. It is efficiently taken into the room without being diffracted.
Note that the angle φ _n of the gradient of the surface of the thin film constituting the lattice line 22 with respect to the normal lines of the first main surface 18 and the second main surface 19 of the transparent resin layer 10 (the first main surface of the transparent resin layer 10). The gradient angle φ _g ) and the grating line spacing d (pitch Pp) of the surface of the thin film constituting the grating line 22 with respect to the surface 18 and the second main surface 19 are as described in the above-described design method. It may be constant throughout 1 and may vary continuously or partially.

<Manufacturing method of window glass>
The window glass of the present invention is produced, for example, through the following steps (I) to (III).
(I) A step of producing a diffraction grating sheet.
(II) A step of attaching a diffraction grating sheet and a glass plate to obtain a window glass body.
(III) A step of obtaining the window glass of the present invention by disposing a solar cell on at least one side of the window glass body.

[Step (I)]
Examples of the method for producing a diffraction grating sheet include a method having the following step (a), step (b), and step (c) in this order.
(A) A first layer made of a transparent resin, wherein one surface is a first main surface and the other surface is a concavo-convex surface in which a plurality of ridges are formed in parallel to each other and at a predetermined pitch Pp. Forming.
(B) Diffraction consisting of a plurality of lattice lines by dry-coating a material having a refractive index different from that of the transparent resin layer on at least a part of the surface of the ridge formed on the first layer. Forming a lattice;
(C) A step of forming the transparent resin layer including the first layer and the second layer by forming the second layer including the transparent resin on the uneven surface of the first layer and the surface of the diffraction grating. .

Moreover, as a manufacturing method of the diffraction grating sheet 1 which has a transparent base material, the method which has the following process (a '), the process (b), and the process (c') in this order, for example is mentioned.
(A ′) On the surface of the first transparent substrate, one surface is an interface with the first transparent substrate, that is, the first main surface, and the other surface has a plurality of protrusions parallel to each other and A step of forming a first layer made of a transparent resin, which is an uneven surface formed at a predetermined pitch Pp.
(B) Diffraction consisting of a plurality of lattice lines by dry-coating a material having a refractive index different from that of the transparent resin layer on at least a part of the surface of the ridge formed on the first layer. Forming a lattice;
(C ′) a first transparent substrate having a first layer and a diffraction grating formed on the surface, and a second transparent substrate having a coating film made of the photocurable composition formed on the surface, The step of forming a transparent resin layer composed of the first layer and the second layer by bonding the layer and the diffraction grating so that the coating film is in contact, and then photocuring the coating film to form the second layer .

Specifically, as a method for manufacturing the diffraction grating sheet 1 of FIG. 4, for example, a method including the following step (a ″), step (b ″), and step (c ″) can be mentioned.
(A ″) On the surface of the first transparent substrate 32, one surface is an interface with the first transparent substrate 32 (that is, the first main surface 18), and the other surface is the first main surface 18. Forming a first layer 14 made of a transparent resin, wherein the plurality of ridges 12 having first side surfaces that are inclined with respect to the surface are uneven surfaces formed in parallel with each other at a predetermined pitch Pp.
(B ″) On the first side surface of the ridge 12 formed on the first layer (on the right side surface of each ridge 12 in FIG. 4), a material having a refractive index different from that of the transparent resin layer 10 is used. A step of forming a diffraction grating 20 composed of a plurality of grating lines 22 by dry coating to form a thin film (grating lines 22).
(C ″) a first transparent substrate 32 on which the first layer 14 and the diffraction grating 20 are formed, and a second transparent substrate 34 on which a coating film made of a photocurable composition is formed. The first layer 14 and the second layer 16 are formed by bonding the first layer 14 and the diffraction grating 20 so that the coating film is in contact with each other and then photocuring the coating film to form the second layer 16. Forming a transparent resin layer 10 comprising:

(Description of specific examples of step (a), step (a ′), step (a ″))
Examples of a method for producing the first layer 14 include an imprint method (an optical imprint method and a thermal imprint method), a lithography method, and the like. The imprint method is preferable from the viewpoint that the area can be increased, and the optical imprint method is particularly preferable from the point that the ridges 12 can be formed with higher productivity and the groove of the mold can be transferred with high accuracy.

In the optical imprint method, for example, a mold in which a plurality of grooves are formed in parallel with each other and at a predetermined pitch Pp is formed by a combination of electron beam drawing and etching. This is a method of transferring to a photocurable composition applied to the surface of the substrate 32 and simultaneously photocuring the photocurable composition.

Specifically, the production of the first layer 14 by the photoimprint method is preferably performed through the following steps (i) to (iv).
(I) A step of applying a photocurable composition to the surface of the first transparent substrate 32.
(Ii) As shown in FIG. 13, the photocurable composition is formed such that the groove 40 is in contact with the photocurable composition 24 in the mold 40 in which the plurality of grooves 42 are formed in parallel to each other and at a predetermined pitch Pp. The process of pressing against 24.
(Iii) In a state where the mold 40 is pressed against the photocurable composition 24, the photocurable composition 24 is cured by irradiating radiation (ultraviolet rays, electron beams, etc.), and a plurality of grooves 40 corresponding to the grooves 42 of the mold 40 are cured. The process of producing the 1st layer 14 which has the protruding item | line 12.
(Iv) A step of separating the mold 40 from the first layer 14.

Specifically, the production of the first layer 14 by the thermal imprint method is preferably performed through the following steps (i) to (iii).
(I) A step of forming a thermoplastic resin transfer film on the surface of the first transparent substrate 32, or a process of producing a thermoplastic resin transfer film.
(Ii) A glass 40 having a glass transition temperature (Tg) of a thermoplastic resin such that the groove 42 is in contact with the film to be transferred or the film to be transferred, or the mold 40 in which the plurality of grooves 42 are formed in parallel with each other and at a constant pitch Pp. A step of producing a first layer 14 having a plurality of ridges 12 corresponding to the grooves 42 of the mold 40 by being pressed against a film to be transferred or a film to be transferred heated to a melting point (Tm) or higher.
(Iii) A step of separating the mold 40 from the first layer 14 by cooling the first layer 14 to a temperature lower than Tg or Tm.

Examples of the material of the mold 40 used in the imprint method include silicon, nickel, quartz glass, and resin.
When a resin film is used for the first transparent substrate 32, the imprint method can be performed by a roll-to-roll method.

(Description of specific examples of step (b) and step (b ″))
The lattice lines 22 are selectively formed on the surface of the side surface of the ridge 12 of the first layer 14 by dry-coating a material having a refractive index different from that of the transparent resin layer 10.

Examples of the dry coating method include a PVD method and a CVD method, and a vacuum deposition method, a sputtering method, and an ion plating method are preferable, and a vacuum deposition method is particularly preferable. As the vacuum deposition method, the oblique deposition method is preferable because the incident direction of the evaporated particles with respect to the first layer 14 can be controlled and the dielectric can be selectively deposited on the surface of the ridge 12.

For example, the lattice lines 22 are formed by the oblique deposition method as follows.
First, as shown in FIG. 14, the following expression (10) is satisfied on the first side surface side with respect to the height direction H of the ridge 12 and substantially perpendicular to the length direction L of the ridge 12. By performing the process of depositing the lattice line material from the direction V1 forming the angle θ ^R (°), the angle of the gradient with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10 is φ _p A thin film that covers a part or the whole of the first side surface of the ridge 12 is formed.
tan (θ ^R ± 10) = (Pp−Hp / tanφ _p ) / Hp (10)

The angle θ ^R (°) in Expression (10) represents the angle for depositing the lattice wire material on the first side surface of the ridge 12 without being blocked by the adjacent ridge 12, and the distance between the top of the bottom and next to the ridge 12 of the first side (i.e., the distance minus the Hp / tan [phi _p from the pitch Pp of the ridges _{12 (Pp-Hp / tanφ p} )), next to the ridge 12 It is determined from the height Hp. “± 10” is a swing width.
The angle θ ^R (°) preferably satisfies tan (θ ^R ± 7) = (Pp−Hp / tanφ _p ) / Hp, and tan (θ ^R ± 5) = (Pp−Hp / tanφ _p ) / Hp. It is more preferable to satisfy.

(Description of specific examples of step (c), step (c ′), step (c ″))
As shown in FIG. 15, the first transparent substrate 32 having the first layer 14 and the diffraction grating 20 formed on the surface, and the second transparent having the coating film 26 made of the photocurable composition formed on the surface. The substrate 34 is bonded so that the coating layer 26 is in contact with the first layer 14 and the diffraction grating 20.
Next, the transparent resin layer 10 including the first layer 14 and the second layer 16 is formed by photocuring the coating film 26 to form the second layer 16.

(Other forms)
The manufacturing method of the diffraction grating sheet may be any method including the above-described steps (a) to (c), and the above-described steps (a ′) to (c ′) and steps (a ″) to (c ″) are performed. The manufacturing method of the illustrated diffraction grating sheet is not limited.

For example, the first side surface of the ridge 12 may not have a gradient with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10, that is, the first main surface. 18 and the second major surface 19 may be perpendicular. Further, the second side surface of the ridge 12 may have a gradient with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10. Further, the top of the ridge 12 may be a flat surface.
Moreover, the surface of the thin film of the lattice line material constituting the lattice line 22 may be formed on the second side surface of the ridge 12 or may be formed on the top surface of the ridge 12.
Moreover, when manufacturing the diffraction grating sheet | seat which has the 1st transparent substrate 32 on the surface of the transparent resin layer 10, and does not have the 2nd transparent substrate 34, the said process (c ') is changed as follows. do it.
(C ′) A coating film made of the photocurable composition is formed on the diffraction grating side surface of the first transparent substrate on which the first layer and the diffraction grating are formed, and then the coating film is photocured. Forming a transparent resin layer comprising the first layer and the second layer by forming the second layer.

[Process (II)]
The window glass body is a known method, that is, in the case of the laminated glass of the first embodiment, according to the known laminated glass manufacturing method. In the case of the multilayer glass of the second embodiment, the window glass body is a known multilayer glass. By the manufacturing method, in the case of the sheet sticking glass of 3rd Embodiment, it manufactures with the manufacturing method of a well-known sheet sticking glass.

[Process (III)]
The window glass can be manufactured by a method in which the solar cell 62 is bonded to at least one side of the window glass main body, or a method in which the window glass main body is fitted in a frame body in which the solar cell 62 is provided in at least one side. . In the case of the multilayer glass of the second embodiment, the step (II) and the step (III) are performed simultaneously.

<Effect>
In the window glass of this invention demonstrated above, since the window glass main body has a diffraction grating, the amount of infrared rays can be controlled according to the incident angle of sunlight.
Moreover, since the solar cell is arrange | positioned at the at least 1 edge | side of the window glass main body, the infrared light energy which did not permeate | transmit can be used effectively.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Example 1 is an example and Example 2 is a comparative example.

(Solar radiation transmittance)
The transmittance was measured at an incident angle of 0 ° to 80 ° using an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, UV3600). The incident angle corresponds to θ ₀ in FIGS. 11 and 12. The solar transmittance was determined by simulation using the solar transmittance measurement software from the obtained spectrum (300-2100 nm).

(Photocurable composition 1)
To a 1000 mL four-necked flask equipped with a stirrer and a condenser,
60 g of monomer 1 (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-DPH, dipentaerythritol hexaacrylate),
40 g of monomer 2 (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-NPG, neopentyl glycol diacrylate),
4.0 g of photopolymerization initiator (manufactured by Ciba Specialty Chemicals, IRGACURE907),
Fluorine-containing surfactant (manufactured by Asahi Glass Co., Ltd., co-oligomer of fluoroacrylate (CH ₂ ═CHCOO (CH ₂ ) ₂ (CF ₂ ) ₈ F) and butyl acrylate), fluorine content: about 30% by mass, mass average molecular weight: About 3000) 0.1 g,
1.0 g of a polymerization inhibitor (Q1301 manufactured by Wako Pure Chemical Industries, Ltd.) and 65.0 g of cyclohexanone were added.
The flask was stirred and homogenized for 1 hour at room temperature and in a light-shielded state. Next, 100 g (solid content: 30 g) of colloidal silica was slowly added while stirring in the flask, and the mixture was further homogenized by stirring for 1 hour while keeping the temperature of the flask at room temperature and light shielding. Next, 340 g of cyclohexanone was added, and the solution was stirred for 1 hour with the inside of the flask at room temperature and light-shielded to obtain a solution of the photocurable composition 1. The refractive index after curing of the photocurable composition 1 was 1.45.

[Example 1]
(Diffraction grating design)
The gradient angle φ _g of the surface of the thin film constituting the lattice line with respect to the first main surface and the second main surface of the transparent resin layer and the pitch Pp of the lattice line 22 are the incident angle θ _{0 of the} infrared ray to be diffracted. Is set to 60 °, and the wavelength λ of infrared rays to be diffracted is set to 800 nm, and based on the above-described diffraction grating design method, a grating with respect to the normal lines of the first main surface and the second main surface of the transparent resin layer The gradient angle φ _{n on} the surface of the thin film constituting the line and the lattice line spacing d in the normal direction of the lattice line were calculated. The results are shown in Table 1.

(Process (I))
Step (a ′):
The photocurable composition 1 was applied by spin coating to the surface of a 50 μm thick highly transparent polyethylene terephthalate (PET) film (Toyobo Co., Ltd., A4300, 100 mm × 100 mm, refractive index (589 nm): 1.65). A coating film of the photocurable composition 1 was formed.
Nickel mold in which a plurality of grooves are formed in parallel with each other at a predetermined pitch (area: 150 mm × 150 mm, pattern area: 100 mm × 100 mm, groove pitch Pp: 0.37 μm, groove depth Hp: 1.5 μm , Groove length: 100 mm, groove cross-sectional shape: substantially right triangle), photocurable at 0.5 MPa (gauge pressure) at 25 ° C. so that the groove is in contact with the coating film of the photocurable composition 1 Pressed against the coating film of composition 1.
While maintaining this state, the PET film side was irradiated with light of a high-pressure mercury lamp (frequency: 1.5 kHz to 2.0 kHz, main wavelength light: irradiation energy at 255 nm, 315 nm and 365 nm, 365 nm: 1000 mJ) for 15 seconds. A curable composition 1 is cured to form a first layer having a plurality of ridges corresponding to the grooves of the mold (ridge pitch Pp: 0.37 μm, ridge height Hp: 1.5 μm, transparent resin The slope angle φ _p of the first side surface of the ridge with respect to the first main surface 18 and the second main surface 19 of the layer 10 was formed. The mold was slowly separated from the first layer.

Step (b):
Using a vacuum deposition device (SEC-16CM, Showa Vacuum Co., Ltd.) that can change the inclination of the PET film with the first layer facing the deposition source, oblique deposition is performed on the first side surface of the first layer of protrusions. Zirconia was vapor-deposited by the method, and lattice lines (lattice line pitch Pp: 0.37 μm, lattice line height Hg: 1.5 μm, lattice lines formed of a thin film of zirconia (refractive index (589 nm): 2.00) Thickness Dg: 72 nm, and the gradient angle φ _g of the surface of the thin film constituting the lattice lines with respect to the first main surface 18 and the second main surface 19 of the transparent resin layer 10 was formed.
At this time, a direction V1 that is substantially perpendicular to the length direction L of the ridge and forms an angle θ ^R with respect to the height direction H of the ridge on the first side surface side (that is, the first side surface side). ) deposited performed once from and shows the angle theta ^R and the vapor deposition in a film thickness of the convex strip is formed in a flat region that is not formed (i.e. deposition amount) Dg 'in Table 1 in the vapor deposition Angle and thickness. In addition, the thickness Dg of the lattice line is a target thickness designed by simulation, and the deposition amount Dg ′ was adjusted so as to be the thickness. Dg ′ was measured by a film thickness monitor using a crystal resonator as a film thickness sensor.

Step (c ′):
The photocurable composition 1 was applied to the surface of a 50 μm thick PET film (Toyobo Co., Ltd., A4300, 100 mm × 100 mm) by a spin coating method to form a coating film of the photocurable composition 1.
A PET film (second transparent substrate) having a coating film made of the photocurable composition 1 formed on the surface of a PET film (first transparent substrate) having the first layer and diffraction grating formed on the surface. The high pressure mercury lamp (frequency: 1.5 kHz to 2.0 kHz, main frequency) was pressed with 0.5 MPa (gauge pressure) at 25 ° C. so that the coating film was in contact with the first layer and the diffraction grating. (Wavelength light: irradiation energy at 255 nm, 315 nm, 365 nm, and 365 nm: 1000 mJ) was irradiated for 15 seconds. The photocurable composition 1 was cured to form a second layer, whereby a transparent resin layer composed of the first layer and the second layer was formed, and the diffraction grating sheet 1 shown in FIG. 4 was obtained.

(Process (II))
Two sheets of float glass plate (100 mm × 100 mm × thickness 2 mm, refractive index (589 nm): 1.52) and an automotive window glass interlayer film (Sekisui Chemical Co., Ltd., thickness 0.78 mm) disposed on the inside Sandwiching the diffraction grating sheet 1 obtained by the above-mentioned step (c ′) by two sheets of polyvinyl butyral film, refractive index (589 nm): 1.48), and deaeration for 4 minutes under a reduced pressure of 720 mmHg, In the deaerated state, it was placed in an oven at 120 ° C. for 30 minutes. A sandwich body in which a glass plate and an intermediate film are pre-pressed is placed in an autoclave and subjected to thermocompression bonding at a pressure of 1.3 MPa and a temperature of 135 ° C. to obtain a window glass body (laminated glass) shown in FIG. It was. Table 1 shows the solar transmittance at an incident angle of 0 ° to 80 °.

(Process (III))
Solar cells 62 are arranged adjacent to the upper and lower sides of the window glass body (laminated glass) to obtain the window glass 3 shown in FIG. That is, the length direction of the grating lines of the diffraction grating in the diffraction grating sheet is such that the light receiving surface of the solar cell 62 is in contact with the end face of the upper side and the lower side of the window glass body (laminated glass). The solar cells are arranged so as to be parallel to the upper side and the lower side.
As the solar cell 62, a single crystal silicon type solar cell is used. FIG. 16 shows the spectral sensitivity characteristics (relationship between wavelength and quantum efficiency) of the single crystal silicon solar cell element.

Of the sunlight incident on the window glass of Example 1 at an incident angle θ ₀ of 60 °, −1st order diffracted light diffracted by the diffraction grating and reflected light reflected in the window glass, that is, confined inside the window glass, FIG. 17 shows a spectrum of light emitted from the upper side and the lower side of the glass body to the solar cell side.
The amount of power generated by the solar cell was calculated assuming that all the light in FIG. 17 was incident on the solar cell. The results are shown in Table 1.

[Example 2]
Table 1 shows the solar transmittance at an incident angle of 0 ° to 80 ° for a float glass sheet (FL, thickness 4 mm) manufactured by Asahi Glass Co., Ltd.
A window glass with a solar cell is obtained in the same manner as in Example 1 except that the above-mentioned float plate glass is used instead of the window glass main body (laminated glass) of Example 1.

Of the sunlight that is incident on the window glass of Example 2 at an incident angle θ ₀ of 60 °, the reflected light reflected in the window glass, that is, confined inside the window glass, from the upper and lower sides of the window glass to the solar cell side. The spectrum of the emitted light is shown in FIG.
The amount of power generated by the solar cell was calculated assuming that all the light in FIG. 17 was incident on the solar cell. The results are shown in Table 1.

The window glass of the present invention efficiently blocks the infrared rays of sunlight entering the room in the summer to suppress the indoor temperature rise, and efficiently takes the infrared rays of the sunlight into the room in the winter to increase the indoor temperature. Building window glass, vehicle window glass (car roof glass, rear glass, windshield, etc.) that can be used as electrical energy by directing infrared light energy blocked in the summer to solar cells ) Is useful.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2011-149070 filed on July 5, 2011 are incorporated herein as the disclosure of the present invention. .

DESCRIPTION OF SYMBOLS 1 Diffraction grating sheet 2 Diffraction grating sheet 3 Window glass 4 Window glass 5 Window glass 6 Window glass main body 10 Transparent resin layer 18 1st main surface 19 2nd main surface 20 Diffraction grating 22 Grid line 32 1st transparent substrate 34 Second transparent substrate 50 Glass plate 52 Intermediate film 62 Solar cell

Claims

A window glass body having a diffraction grating;
A window glass comprising: a solar cell disposed on at least one side of the window glass body.
The window glass according to claim 1, wherein the window glass body has a diffraction grating sheet provided with a glass plate and the diffraction grating.
The diffraction grating sheet is
A transparent resin layer having a first main surface and a second main surface parallel to each other;
A diffraction grating composed of a plurality of grating lines arranged in parallel to each other at a predetermined pitch,
The lattice line is made of a thin film of a material having a refractive index different from that of the transparent resin layer,
The grating line is a diffraction grating sheet embedded in the transparent resin layer so that the length direction extends parallel to the first main surface and the second main surface of the transparent resin layer, The window glass according to claim 2.
The transparent resin such that the lattice lines extend in parallel in the length direction with respect to the first main surface and the second main surface of the transparent resin layer, and the surface of the thin film has a gradient. The window glass according to claim 3, which is embedded in the layer.
The window glass according to claim 3 or 4, wherein the lattice lines are made of a dielectric thin film having a refractive index larger than that of the transparent resin layer.
6. The window glass according to claim 5, wherein a refractive index of the dielectric thin film constituting the lattice line is 0.0001 to 1.8 higher than a refractive index of the transparent resin layer.
The window glass according to any one of claims 3 to 6, wherein the diffraction grating sheet further includes a first transparent substrate in contact with the first main surface.
The window glass body is a laminated glass in which two glass plates and a diffraction grating sheet sandwiched between them are bonded via an intermediate film. Window glass.
The window glass main body is a multi-layer glass in which two glass plates are arranged at a predetermined interval and a diffraction grating sheet is adhered to the inner surface of at least one glass plate. The window glass according to claim 1.
The window glass according to any one of claims 2 to 7, wherein the window glass body has a diffraction grating sheet attached to the surface of a glass plate.
The solar cell is arranged on a side parallel to a length direction of a grating line of the diffraction grating in the diffraction grating sheet among at least one side of the window glass body. Window glass according to item.