JP7500802B2 - Heat reflecting optical body - Google Patents

Description

The present invention relates to a heat reflecting optical body.

In recent years, optical films that are intended to provide various effects such as absorption and reflection to incident light have become widely known. These optical films are available in various configurations depending on the intended function. One of them is an optical film having an internal interface with a concave-convex shape, on which a thin film is formed. For example, Patent Document 1 discloses a retroreflective polarizer as an optical film of the above configuration, which comprises a first substrate having an uneven surface on which multiple prisms are arranged in a one-dimensional manner, a laminated film formed on this uneven surface, and a second substrate formed on this laminated film.

One example of the uneven shape of such an optical film is a shape in which multiple columnar protrusions extending in one direction are linearly arranged in one direction, as shown in Figures 3A to 3C of Patent Document 2. Here, the height of the columnar protrusions is the same at every position, and the distance between the tops of adjacent protrusions is the same at every position.

JP 2004-78234 A JP 2011-128512 A

An optical film having the above-mentioned shape is arranged on a window pane, for example, as a heat ray reflective film that retroreflects sunlight, with the one-dimensionally arranged direction being parallel to the horizontal direction.
In this case, the light coming from the sun, for example, coming from above in the southeast, is reflected upward in the southwest. This reflected light is the sunlight, which is the light source, reflected locally, so in the case of a heat ray retroreflection function, it will reflect heat rays. If there is a building in the straight direction of the reflected light, it will be exposed to heat rays and suffer heat damage.
Furthermore, if the reflected light is visible light, it can be dazzling and may impair the view from the window.
For this reason, there is currently a demand for reducing localized strong reflection in regular reflection in optical bodies.

The present invention aims to provide an optical body having a convex shape in which multiple columnar convex portions extending in one direction are arranged one-dimensionally in one direction, and capable of reducing strong localized reflection in regular reflection.

The means for solving the above problems are as follows.
<1> A first optical layer having a convex surface on which a plurality of columnar protrusions extending in one direction are one-dimensionally arranged in one direction;
an inorganic layer disposed on the surface of the first optical layer on the side having the convex shape;
a second optical layer disposed on the inorganic layer side so that the convex shape is embedded in the second optical layer;
having
The optical body is characterized in that the convex shape satisfies at least one of the following (1) to (4).
(1) The height of each columnar protrusion varies in the extension direction.
(2) The top of each columnar protrusion meanders in a direction perpendicular to both the extension direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped protrusion and a cylindrical protrusion having a curved surface are adjacent to each other.
<2> The optical body according to <1>, wherein the inorganic layer is a wavelength selective reflective layer.
<3> The optical body according to <1>, wherein the inorganic layer is semi-transparent.
<4> The optical body according to any one of <1> to <3>, wherein the first optical layer and the second optical layer have transparency.
<5> The optical body according to any one of <1> to <4>, which is attached to a window glass for use.

The present invention provides an optical body having a convex shape in which multiple columnar protrusions extending in one direction are arranged one-dimensionally in one direction, and which can reduce strong localized reflection in regular reflection.

FIG. 1A is a diagram for explaining a state in which sunlight is reflected by a window to which an optical film having a heat-reflecting structure shown in FIG. 3A is attached (part 1). FIG. 1B is a diagram (part 2) for explaining a state in which sunlight is reflected by a window to which an optical film having a heat-reflecting structure shown in FIG. 3A is attached. FIG. 2A is a diagram for explaining a state in which sunlight is reflected by a window to which an optical film having a heat-reflecting structure shown in FIG. 4A is attached (part 1). FIG. 2B is a diagram (part 2) for explaining a state in which sunlight is reflected by a window to which the optical film having the heat-reflecting structure shown in FIG. 4A is attached. FIG. 3A is a perspective view of a first optical layer in a conventional example. FIG. 3B is a top view of the first optical layer in a conventional example. FIG. 3C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 3A and 3B. FIG. 3D is a perspective view of the master of FIG. 3C in a flat plate shape. FIG. 4A is a perspective view of an example of a first optical layer of an optical body of the present invention. FIG. 4B is a top view of an example of a first optical layer of an optical body of the present invention. FIG. 4C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 4A and 4B. FIG. 4D is a perspective view of the master of FIG. 4C in a flat plate shape. FIG. 5A is a perspective view of another example of the first optical layer of the optical body of the present invention. FIG. 5B is a top view of another example of the first optical layer of the optical body of the present invention. FIG. 5C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 5A and 5B. FIG. 5D is a perspective view of the master of FIG. 5C in a flat plate shape. FIG. 6A is a perspective view of another example of the first optical layer of the optical body of the present invention. FIG. 6B is a top view of another example of the first optical layer of the optical body of the present invention. FIG. 6C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 6A and 6B. FIG. 6D is a perspective view of the master of FIG. 6C in a flat plate shape. FIG. 7A is a perspective view of another example of the first optical layer of the optical body of the present invention. FIG. 7B is a top view of another example of the first optical layer of the optical body of the present invention. FIG. 7C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 7A and 7B. FIG. 7D is a perspective view of the master of FIG. 7C in a flat plate shape. FIG. 8A is a perspective view of another example of the first optical layer of the optical body of the present invention. FIG. 8B is a top view of another example of the first optical layer of the optical body of the present invention. FIG. 8C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 8A and 8B. FIG. 8D is a perspective view of the master of FIG. 8C in a flat plate shape. FIG. 9A is a perspective view of another example of the first optical layer of the optical body of the present invention. FIG. 9B is a top view of another example of the first optical layer of the optical body of the present invention. FIG. 9C is a schematic diagram of a master and a cutting tool for producing the first optical layer in FIGS. 9A and 9B. FIG. 9D is a perspective view of the master of FIG. 9C in a flat plate shape. FIG. 10A is a cross-sectional view for explaining the height of the convex portions of the first optical layer (part 1). FIG. 10B is a cross-sectional view for explaining the height of the convex portions of the first optical layer (part 2). FIG. 11A is a cross-sectional view (part 1) for explaining the distance (pitch) between adjacent convex portions of the first optical layer. FIG. 11B is a cross-sectional view (part 2) for explaining the distance (pitch) between adjacent convex portions of the first optical layer. FIG. 12 is a cross-sectional view of an example of the optical body of the present invention. FIG. 13A is a cross-sectional view for explaining an example of the function of the optical body of the present invention. FIG. 13B is a cross-sectional view for explaining an example of the function of the optical body of the present invention. FIG. 14 is a perspective view showing the relationship between incident light incident on an optical body having wavelength-selective reflectivity and reflected light reflected by the optical body. FIG. 15A is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 1). FIG. 15B is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 2). FIG. 15C is a process diagram for explaining an example of a method for manufacturing an optical body according to an embodiment of the present invention (part 3). FIG. 16A is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 4). FIG. 16B is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 5). FIG. 16C is a process diagram for explaining an example of a method for manufacturing an optical body according to an embodiment of the present invention (part 6). FIG. 17A is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 7). FIG. 17B is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 8). FIG. 17C is a process diagram for explaining an example of a method for manufacturing an optical body according to one embodiment of the present invention (part 9). FIG. 18A is a diagram for explaining the average height (AH), the amplitude (A), the period (Pe), and the tilt angle (E) at which the amount of maximum change is reached. FIG. 18B is a diagram for explaining the shift (ΔPh) in the periodic change. FIG. 19 is a diagram for explaining the amplitude (Ab), the period (Peb), the tilt angle (Eb) at which the amount of maximum change occurs, and the shift in periodic change (ΔPhb). FIG. 20 is a graph showing the relationship between the amplitude and the relative value of the reflected light intensity. FIG. 21 is a graph showing the relationship between the amplitude/period and the relative value of the reflected light intensity. FIG. 22 is a graph showing the relationship between the maximum change angle and the relative value of the reflected light intensity. FIG. 23 is a graph showing the relationship between the amplitude and the relative value of the upward reflection component. FIG. 24 is a graph showing the relationship between the amplitude/period and the relative value of the upward reflection component. FIG. 25 is a graph showing the relationship between the maximum change angle and the relative value of the upward reflection component. FIG. 26 is a diagram showing a state in which the optical body is attached to float glass using an adhesive.

(Optical body)
The optical body of the present invention has at least a first optical layer, an inorganic layer, and a second optical layer, and may further have other members as necessary.

When a conventional optical film 100A having a convex shape in which a plurality of columnar convex portions extending in one direction are arranged one-dimensionally in one direction is placed on a window glass such that the direction of the one-dimensional arrangement is parallel to the horizontal direction, light entering the window 100 from the sun 101 is normally specularly reflected and is reflected toward the sky at the point where the light enters the window 100, with the columnar arrangement direction extending in one direction as the axis ( FIGS. 1A and 1B ).
In such a case, the sunlight is reflected locally (FIGS. 1A and 1B). Therefore, if there is an adjacent building 102, the building 102 will be exposed to the reflected sunlight. Therefore, if heat rays are reflected, the building 102 will be exposed to areas where sunlight does not normally penetrate or areas where sunlight is shining in, causing heat damage (FIG. 1A).

Therefore, the inventors conducted intensive research and found that it is possible to reduce strong localized regular reflection by disrupting the uniformity in a convex shape in an optical body in which a plurality of columnar protrusions extending in one direction are one-dimensionally arranged in one direction, specifically, by making the convex shape in an optical body in which a plurality of columnar protrusions extending in one direction are one-dimensionally arranged in one direction satisfy at least any one of the following (1) to (4), which led to the completion of the present invention.
(1) The height of each columnar protrusion varies in the extension direction.
(2) The top of each columnar protrusion meanders in a direction perpendicular to both the extension direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped protrusion and a cylindrical protrusion having a curved surface are adjacent to each other.

When optical film 100B of the present invention, which has a convex shape in which a plurality of columnar protrusions extending in one direction are one-dimensionally arranged in one direction and the convex shape satisfies at least any one of the above (1) to (4), is placed on a window glass so that the direction of the one-dimensional arrangement is parallel to the horizontal direction, light entering window 100 from sun 101 is reflected toward the sky at the point where the light enters window 100, with the direction of the columnar arrangement extending in one direction as an axis ( FIGS. 2A and 2B ).
In such a case, the sunlight is usually reflected strongly locally (FIGS. 1A and 1B). On the other hand, when the optical film 100B of the present invention is used, the localized specular reflection is reduced (FIGS. 2A and 2B). Therefore, even if there is an adjacent building 102, the building 102 is less likely to be damaged by heat.

An embodiment in which the convex shape satisfies at least one of the above (1) to (4) will be described below along with an example of a manufacturing method.

First, the first optical layer of the conventional example will be described.
Fig. 3A is a perspective view of a first optical layer 91 in a conventional example, and Fig. 3B is a top view of the first optical layer 91 in the conventional example.
In the first optical layer 91 shown in FIGS. 3A and 3B, a plurality of columnar protrusions 91A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 3B, the thick straight solid lines indicate the tops of the columnar protrusions 91A, and the dashed lines indicate the valley bottoms between the columnar protrusions.
As shown in Figures 3A and 3B, in the conventional first optical layer 91, the height of the columnar convex portion 91A is the same at every position, and the distance between the tops of adjacent convex portions is the same at every position.
The first optical layer 91 in FIGS. 3A and 3B is fabricated, for example, as follows.
The first optical layer 91 is produced by transferring a convex shape formed on a master.
As shown in Fig. 3C, the master 95 is, for example, in the form of a roll. While rotating the master 95, a cutting tool 96 having a tip of a predetermined shape is applied to the master 95 so as to cut a predetermined depth, thereby cutting the master 95. When cutting of one revolution of the master 95 is completed, the cutting tool 96 is moved a predetermined distance in a direction perpendicular to the direction of rotation, and cutting of the master 95 is resumed. At this time, the cutting depth is set to the same depth as before. By repeating this process, a master 95 having a predetermined convex shape is obtained. Fig. 3D is a perspective view of the master 95 as shown in a flat plate shape.
Alternatively, while rotating a roll-shaped master 95, a cutting tool 96 having a tip of a predetermined shape is brought into contact with the master 95 so as to cut a predetermined depth, and the number of rotations of the roll and the travel distance of the cutting tool are determined so that cutting can be performed in a spiral shape, thereby enabling continuous processing and improving processing efficiency.
The first optical layer can be obtained by pressing this master 95 against an uncured resin sheet, or by pressing an uncured resin sheet against this master 95, transferring the convex shape of the master 95 to the resin sheet, and curing the resin sheet.

Next, one embodiment of the first optical layer of the present invention will be described.
In the first optical layer 11 shown in FIGS. 4A and 4B, a plurality of columnar protrusions 11A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 4B, the thick straight solid lines indicate the tops of the columnar protrusions 11A, and the dashed lines indicate the valley bottoms between the columnar protrusions.
4A and 4B , in the first optical layer 11 of one embodiment of the present invention, the height of the columnar convex portion 11A changes continuously. Note that in the top view of FIG. 4B , both the peak and the valley are linear.
The first optical layer 11 in FIG. 4A and FIG. 4B is produced, for example, as follows.
The first optical layer 11 is produced by transferring a convex shape formed on a master.
As shown in FIG. 4C, the master 15 is, for example, in the form of a roll. While rotating the master 15, a cutting tool 16 having a tip of a predetermined shape is applied to the master 15 to cut the master 15. By applying vertical movement to the cutting tool 16 during cutting, cutting grooves with continuously different cutting depths are obtained. When cutting of one circumference of the master 15 is completed, the cutting tool 16 is moved a predetermined distance in a direction perpendicular to the rotation direction to resume cutting of the master 15. At this time, cutting is performed so that the vertical movement of the cutting tool 16 is performed at the same timing as before. That is, in the multiple cutting grooves generated by cutting, the timing of the vertical movement is made the same so that the cutting depth is the same in the direction perpendicular to the rotation direction of the master 15. By repeating this, a master 15 having a convex shape in which the height of the columnar convex portion changes continuously is obtained. By making the timing of the vertical movement the same, the top of the columnar convex portion becomes straight when viewed from the top. FIG. 4D is a perspective view of the master 15 in the form of a flat plate.
The cutting tool 16 can be moved up and down by using a driving means such as a piezoelectric element or a solenoid actuator.
The first optical layer 11 can be obtained by pressing this master 15 against an uncured resin sheet, or by pressing an uncured resin sheet against this master 15, transferring the convex shape of the master 15 to the resin sheet, and curing the resin sheet.
Alternatively, instead of the above-mentioned transfer method, a mold (replica) having an inverted shape to which the convex shape of the master 15 is transferred can be produced, and the mold can be pressed against an uncured resin sheet to copy the convex shape of the master 15 onto the resin sheet, and the resin sheet can be cured to obtain the first optical layer 11.

Next, another embodiment of the first optical layer of the present invention will be described.
In the first optical layer 21 shown in FIGS. 5A and 5B, a plurality of columnar protrusions 21A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 5B, the thick wavy solid lines indicate the tops of the columnar protrusions 21A, and the dashed lines indicate the valley bottoms between the columnar protrusions.
5A and 5B , in the first optical layer 21 according to one embodiment of the present invention, the height of the columnar protrusions 21A changes continuously. Note that in the top view of FIG. 5B , the peaks are meandering and the valleys are linear.
The first optical layer 21 in FIGS. 5A and 5B is produced, for example, as follows.
The first optical layer 21 is produced by transferring a convex shape formed on a master.
As shown in FIG. 5C, the master 25 is, for example, in the form of a roll. While rotating the master 25, a cutting tool 26 having a tip of a predetermined shape is applied to the master 25 to cut the master 25. By applying vertical movement to the cutting tool 26 during cutting, cutting grooves with continuously different cutting depths are obtained. When cutting of one circumference of the master 25 is completed, the cutting tool 26 is moved a predetermined distance in a direction perpendicular to the rotation direction, and cutting of the master 25 is resumed. At this time, cutting is performed while applying vertical movement to the cutting tool 26 so that the vertical movement has a different timing from the previous time. That is, in the multiple cutting grooves generated by cutting, the timing of the vertical movement is shifted so that the cutting depth is not always the same in the direction perpendicular to the rotation direction of the master 25. By repeating this, a master 25 having a convex shape in which the height of the columnar convex portion changes continuously is obtained. By shifting the timing of the vertical movement, the top of the columnar convex portion becomes meandering and wavy when viewed from the top. FIG. 5D is a perspective view of the master 25 in the form of a flat plate.
Alternatively, when cutting the master 25 by applying a cutting tool 26 having a tip of a predetermined shape to the master 25 so as to cut the master 25 to a predetermined depth while rotating the roll-shaped master 25, the number of rotations of the roll and the moving distance of the cutting tool are determined and created so that cutting can be performed in a spiral shape, thereby enabling continuous processing and improving processing efficiency. In this case, by vertically moving the cutting tool 26 while shifting the timing so that the cutting depth is not always the same in the direction perpendicular to the rotation direction of the master 25, a cut groove as shown in Fig. 5D is obtained.
A mold (replica) having an inverted shape to which the convex shape of this master 25 is transferred is created, and this mold is pressed against an uncured resin sheet to copy the convex shape of the master 25 onto the resin sheet, and the resin sheet is cured to obtain the first optical layer 21.
The first optical layer 21 can also be obtained by pressing the master 25 against an uncured resin sheet, or by pressing an uncured resin sheet against the master 25, transferring the convex shape of the master 25 to the resin sheet, and curing the resin sheet. In this case, however, the top view of the first optical layer 21 is in a state in which the solid lines and dashed lines are interchanged in Fig. 5B. That is, the tops of the columnar convex portions are straight lines when viewed from above, and the valley bottoms between the columnar convex portions are meandering and wavy when viewed from above.

Next, another embodiment of the first optical layer of the present invention will be described.
In the first optical layer 31 shown in FIGS. 6A and 6B, a plurality of columnar protrusions 31A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 6B, the thick wavy solid lines indicate the tops of the columnar protrusions 31A, and the dashed lines indicate the valley bottoms between the columnar protrusions.
6A and 6B , in the first optical layer 31 according to one embodiment of the present invention, the columnar protrusions 31A have the same height, but the tops of the columnar protrusions 31A meander in a direction perpendicular to the extension direction and the height direction. Note that in the top view of FIG. 6B , both the tops and the bottoms of the valleys meander.
The first optical layer 31 in FIGS. 6A and 6B is fabricated, for example, as follows.
The first optical layer 31 is produced by transferring the convex shape of a master on which the convex shape is formed.
As shown in FIG. 6C, the master 35 is, for example, in the form of a roll. While rotating the master 35, a cutting tool 36 having a tip of a predetermined shape is applied to the master 35 to cut the master 35. During cutting, the cutting tool 36 is moved horizontally left and right to obtain a meandering cut groove without changing the cutting depth. When cutting of one circumference of the master 35 is completed, the cutting tool 36 is moved a predetermined distance in a direction perpendicular to the rotation direction to resume cutting of the master 35. At this time, the timing of the left and right movement is the same as before. That is, the timing of the left and right movement is made the same so that the multiple cut grooves generated by cutting meander in the same shape from the start of cutting to the end of cutting. By repeating this, a master 35 having a convex shape in which the top of each columnar convex portion 31A meanders in a direction perpendicular to the extension direction and height direction is obtained. In this master 35, the height of the columnar convex portion 31A is the same. FIG. 6D is a perspective view of the master 35 in a flat plate form.
The first optical layer 31 can be obtained by pressing this master 35 against an uncured resin sheet, or by pressing an uncured resin sheet against this master 35, transferring the convex shape of the master 35 to the resin sheet, and curing the resin sheet.
Alternatively, instead of the above-mentioned transfer method, a mold (replica) having an inverted shape to which the convex shape of the master 35 is transferred can be produced, and the mold can be pressed against an uncured resin sheet to copy the convex shape of the master 35 onto the resin sheet, and the resin sheet can be cured to obtain the first optical layer 31.

Next, another embodiment of the first optical layer of the present invention will be described.
In the first optical layer 41 shown in FIGS. 7A and 7B, a plurality of columnar protrusions 41A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 7B, the thick wavy solid lines indicate the tops of the columnar protrusions 41A, and the dashed lines indicate the valley bottoms between the columnar protrusions.
7A and 7B , in the first optical layer 41 according to one embodiment of the present invention, the columnar protrusions 41A have the same height, but the tops of the columnar protrusions 41A meander in a direction perpendicular to the extension direction and the height direction. Note that in the top view of FIG. 7B , although the tops meander, the valley bottoms are linear.
The first optical layer 41 in FIGS. 7A and 7B is fabricated, for example, as follows.
The first optical layer 41 is produced by transferring the convex shape of a master on which the convex shape is formed.
As shown in FIG. 7C, the master 45 is, for example, a roll shape. While rotating the master 45, a cutting tool 46 having a tip of a predetermined shape is applied to the master 45 to cut the master 45. During cutting, the cutting tool 46 is made to perform a pendulum motion with the tip as an axis, so that the cutting tip is linear and a meandering cutting groove is obtained. When cutting of one circumference of the master 45 is completed, the cutting tool 46 is moved a predetermined distance in a direction perpendicular to the rotation direction, and cutting of the master 45 is resumed. At this time, the timing of the pendulum motion is the same as before. That is, the timing of the pendulum motion is made the same so that the multiple cutting grooves generated by cutting meander in the same shape from the start of cutting to the end of cutting. By repeating this, a master 45 having a convex shape in which the top of each columnar convex portion 41A meanders in a direction perpendicular to the extension direction and height direction is obtained. In this master 45, the height of the columnar convex portions 41A is the same. FIG. 7D is a perspective view of the master 45 in the form of a flat plate.
A mold (replica) having an inverted shape to which the convex shape of this master 45 is transferred is created, and this mold is pressed against an uncured resin sheet to copy the convex shape of the master 45 onto the resin sheet, and the resin sheet is cured to obtain the first optical layer 41.

Next, another embodiment of the first optical layer of the present invention will be described.
In the first optical layer 51 shown in FIGS. 8A and 8B, a plurality of columnar protrusions 51A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 8B, the thick straight solid lines indicate the tops of the columnar protrusions 51A, and the dashed lines indicate the valley bottoms between the columnar protrusions.
8A and 8B , in the first optical layer 51 of one embodiment of the present invention, adjacent columnar convex portions 51A have different heights. Note that in the top view of FIG. 8B , both the peaks and the valleys are linear.
The first optical layer 51 in FIG. 8 and FIG. 8B is fabricated, for example, as follows.
The first optical layer 51 is produced by transferring the convex shape of a master on which the convex shape is formed.
As shown in FIG. 8C, the master 55 is, for example, in the form of a roll. While rotating the master 55, a cutting tool 56 having a tip 56A of a predetermined shape is applied to the master 55 to cut the master 55. When cutting of one revolution of the master 55 is completed, cutting of the master 55 is resumed from a position moved a predetermined distance in a direction perpendicular to the direction of rotation, using a cutting tool 56 having a tip 56B having a tip shape different from the tip 56A. By repeating this process, a master 55 having a convex shape in which the heights of adjacent columnar convex portions 51A are different can be obtained. FIG. 8D is a perspective view of the master 55 in the form of a flat plate.
The master 55 is pressed against an uncured resin sheet to transfer the convex shape of the master 55 to the resin sheet, and the resin sheet is cured, thereby obtaining the first optical layer 51 .

Next, another embodiment of the first optical layer of the present invention will be described.
In the first optical layer 61 shown in FIGS. 9A and 9B, a plurality of columnar protrusions 61A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 9B, the thick, straight, solid lines indicate the apexes of the triangular prism-shaped protrusions, the thick, straight, alternate long and short dashed lines indicate the apexes of the columnar protrusions having a curved surface, and the dashed lines indicate the valley bottoms between the columnar protrusions.
As shown in FIGS. 9A and 9B , in a first optical layer 61 according to one embodiment of the present invention, a triangular prism-shaped convex portion and a columnar convex portion having a curved surface are adjacent to each other.
The first optical layer 61 in FIG. 9 and FIG. 9B is fabricated, for example, as follows.
The first optical layer 61 is produced by transferring the convex shape of a master on which the convex shape is formed.
As shown in FIG. 9C, the master 65 is, for example, in the form of a roll. While rotating the master 65, a cutting tool 66 having a predetermined triangular tip 66A is applied to the master 65 to cut the master 65. When cutting of one revolution of the master 65 is completed, cutting of the master 65 is resumed from a position moved a predetermined distance in a direction perpendicular to the rotation direction using a cutting tool 66 having a tip 66B having a curved tip shape different from the tip 66A. By repeating this, a master 65 having a convex shape in which a triangular prism-shaped convex portion and a columnar convex portion having a curved surface are adjacent to each other is obtained. FIG. 9D is a perspective view of the master 65 in the form of a flat plate.
A mold (replica) having an inverted shape to which the convex shape of this master 65 is transferred is created, and this mold is pressed against an uncured resin sheet to copy the convex shape of the master 65 onto the resin sheet, and the resin sheet is cured to obtain the first optical layer 61.

<First Optical Layer>
The first optical layer has a convex surface on which a plurality of columnar protrusions extending in one direction are one-dimensionally arranged in one direction.
The first optical layer supports and protects the inorganic layer formed on the textured surface.
The first optical layer has the convex shape as described above. That is, the convex shape satisfies at least one of the following (1) to (4).
(1) The height of each columnar protrusion varies in the extension direction.
(2) The top of each columnar protrusion meanders in a direction perpendicular to both the extension direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped protrusion and a cylindrical protrusion having a curved surface are adjacent to each other.

In the first optical layer, the average height of the convex portions is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 μm to 1,000 μm, more preferably 10 μm to 300 μm, and particularly preferably 20 μm to 100 μm.
Here, the height will be described with reference to the drawings. Figures 10A and 10B are schematic cross-sectional views of the first optical layer in a direction perpendicular to the direction in which the multiple convex portions are one-dimensionally arranged.
The height (H) refers to the height from the bottom to the top of the convex portion in the cross section of the first optical layer 71 in a direction perpendicular to the direction in which the multiple convex portions are one-dimensionally arranged, as shown in Figures 10A and 10B. Here, the bottom (B) of the convex portion corresponds to an imaginary line connecting two valleys that sandwich the convex portion. The height (H) is the distance from the top of the convex portion to the intersection of the perpendicular line from the top of the convex portion to the plane of the first optical layer 71 and the bottom (B) of the convex portion.

In the first optical layer, the average value of the distance (pitch) between the multiple convex portions is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 μm to 3,000 μm, more preferably 20 μm to 900 μm, even more preferably 40 μm to 300 μm, and particularly preferably 45 μm to 90 μm.
Here, the distance (pitch) will be described with reference to the drawings. Figures 11A and 11B are schematic cross-sectional views of the first optical layer in a direction perpendicular to the direction in which the multiple convex portions are one-dimensionally arranged.
11A and 11B, the distance (pitch) (P) refers to the distance between the apexes of adjacent convex portions in a cross section of the first optical layer 71 in a direction perpendicular to the direction in which the multiple convex portions are linearly arranged. Here, when the heights of the apexes of adjacent convex portions are different, the distance (pitch) (P) refers to the distance between the perpendicular line (L _l ) from the apex of one convex portion to the plane of the first optical layer 71 and the perpendicular line (L _r ) from the apex of another convex portion adjacent to the one convex portion to the plane of the first optical layer 71.

The height and distance can be determined, for example, by observing an electron microscope photograph of the cross section.
The average value can be obtained by arbitrarily measuring 50 locations of the convex shape that satisfies at least any one of the above (1) to (4).

The shape of the protrusion is, for example, triangular in a cross section perpendicular to the extension direction.

<When the convex shape satisfies the above (1)>
When the convex shape satisfies the above (1), the average height (AH) of each columnar convex portion may be, for example, 15 μm to 45 μm or 25 μm to 35 μm.
When the convex shape satisfies the above (1), for example, the change in height of each columnar convex portion is periodic, and the period (Pe) of the change may be, for example, 400 μm to 1,200 μm, 600 μm to 1,000 μm, or 700 μm to 900 μm.
When the convex shape satisfies the above (1), for example, the change in height of each columnar convex portion is periodic, and the amplitude (A) of the change is preferably 5 μm to 65 μm from the viewpoint of reducing local upward reflection. In addition to reducing local upward reflection, taking into consideration the processability of master production and the inflow of resin components into the master, the amplitude (A) is more preferably 5 μm to 40 μm, and particularly preferably 10 μm to 30 μm.
When the convex shape satisfies the above (1), the ratio of the amplitude (A) to the period (Pe) [amplitude (μm)/period (μm)] is preferably 0.6% to 7.8%, and from the viewpoints of reducing local reflection of upward reflection and processability, it is more preferably 0.6% to 5.0%, and particularly preferably 1.2% to 3.8%.
The range of change in amplitude can be, for example, a wavy curve with gradually increasing curvature such as a sine wave, a cycloid curve, or an involute curve, or a curve formed by a combination of sine waves of higher harmonics, or a curve formed by a combination of these, and the inclination angle (E) at which the maximum change occurs is preferably in the range of 1.1 deg to 13.7 deg. If the angle range is larger, when the cutting edge of the cutting blade bites into the cutting edge to cut, the cutting blade will scratch the surface after processing, which is undesirable. Therefore, for reasons of master processing, 1.1 deg to 13.7 deg is preferable, 1.1 deg to 9.9 deg is more preferable, and 2.2 deg to 6.7 deg is particularly preferable.
In addition, the shift (ΔPh) in the periodic change in height between adjacent columnar protrusions is preferably 1/4 to 3/4 period, more preferably 1/3 to 2/3 period, even more preferably 2/5 to 3/5 period, and particularly preferably 1/2 period.
Here, the average height (AH), amplitude (A), period (Pe), tilt angle (E) at which the amount of maximum change occurs, and deviation of periodic change (ΔPh) will be explained with reference to the drawings.
18A is a diagram for explaining the average height (AH), amplitude (A), period (Pe), and tilt angle (E) at the maximum change amount, which is a cross-sectional view of a columnar protrusion viewed from a direction perpendicular to the extension direction and thickness direction.
The average height (AH) is the average value from the bottom of the convex portion to the height of the convex portion.
The amplitude (A) is the difference between the maximum height and the minimum height of the change in height.
The period (Pe) is the period of the changing height.
The tilt angle (E) at which the amount of change becomes maximum is the differential value of the change in height at the position where the change in height becomes maximum.
FIG. 18B shows a diagram for explaining the shift (ΔPh) in the periodic change.
In FIG. 18B, the solid curved line indicates the ridgeline of a first columnar protrusion, and the dashed curved line indicates the ridgeline of a second columnar protrusion adjacent to the first columnar protrusion.
The shift (ΔPh) in the periodic change is the shift in the periodic change in height between two adjacent columnar protrusions. In FIG. 18B, the shift (ΔPh) in the periodic change is ½ period.

<When the convex shape satisfies the above (2)>
When the convex shape satisfies the above (2), the average height of each columnar convex portion may be, for example, 15 μm to 45 μm, or 25 μm to 35 μm.
When the convex shape satisfies the above (2), for example, the meandering is periodic, and the period (Peb) of the meandering may be, for example, 400 μm to 1,200 μm, 600 μm to 1,000 μm, or 700 μm to 900 μm.
When the convex shape satisfies the above (2), for example, the meandering is periodic, and the meandering amplitude (Ab) is preferably 5 μm to 65 μm from the viewpoint of reducing local upward reflection. In addition to reducing local upward reflection, taking into consideration the workability of master production and the inflow of resin components into the master, the amplitude (Ab) is more preferably 5 μm to 40 μm, and particularly preferably 10 μm to 30 μm.
When the convex shape satisfies the above (2), the ratio (amplitude/period) of the amplitude (Ab) to the period (Peb) is preferably 0.6% to 7.8%, and from the viewpoints of reducing local reflection of upward reflection and processability, 0.6% to 5.0% is more preferable, and 1.2% to 3.8% is particularly preferable.
The range of change in the meandering can be, for example, a sinusoidal wave, or a cycloidal curve, an involute curve, or a curve formed by a combination of sine waves of higher harmonics, or a curve formed by a combination of these, and the inclination angle (Eb) at which the maximum change occurs is preferably in the range of 1.1 deg to 13.7 deg. If the angle range is larger, the cutting edge of the cutting blade will be larger than the cutting angle when cutting by biting into the cutting edge, and therefore the cutting blade will scratch the surface after processing, which is not preferable. Therefore, for reasons of processing the master plate, 1.1 deg to 13.7 deg is preferable, 1.1 deg to 9.9 deg is more preferable, and 1.1 deg to 6.7 deg is particularly preferable.
Furthermore, the shift (ΔPhb) in the periodic change of the meandering of adjacent columnar protrusions is preferably 1/4 to 3/4 period, more preferably 1/3 to 2/3 period, even more preferably 2/5 to 3/5 period, and particularly preferably 1/2 period.
Here, the amplitude (Ab), period (Peb), tilt angle (Eb) at which the amount of change is maximum, and the shift in periodic change (ΔPhb) will be described with reference to the drawings.
19 is a diagram for explaining the amplitude (Ab), period (Peb), the tilt angle (Eb) at which the amount of change is maximum, and the shift in periodic change (ΔPhb). This diagram is a top view of a columnar protrusion as seen from above.
In FIG. 19, the solid curved lines indicate the ridge lines of the columnar protrusions, and the dashed dotted lines indicate the valley bottoms between the two protrusions.
The amplitude (Ab) is the width of the meander.
The period (Peb) is the period in the periodic meandering.
The tilt angle (Eb) at which the amount of change becomes maximum is the differential value of the change in meandering at the position where the change in meandering is maximum.
In FIG. 19, the shift in periodic change (ΔPhb) is ½ period.

<When the convex shape satisfies the above (3)>
When the convex shape satisfies the above (3), the absolute value of the difference in height between adjacent columnar convex portions is, for example, preferably 5 μm to 65 μm, more preferably 5 μm to 40 μm, and particularly preferably 5 μm to 30 μm.

It is preferable that the change in height in (1), the meandering in (2), the difference in height in (3), and the arrangement of the triangular prism-shaped protrusions and the curved prism-shaped protrusions in (4) are periodic for the following reasons.
It is also possible to randomly arrange the structures (protrusions) in terms of changes. However, if structures with large heights and structures with small heights are arranged in succession as a result of random arrangement, the light reflected once by a structure with a height may pass through a long distance in the resin of the transparent body before hitting a structure that is reflected by the structure with a height again, which may increase the absorption rate and reduce the reflection efficiency. In particular, when the purpose is to retroreflect heat rays on window glass, a high absorption rate may cause a local increase in temperature, which may cause a "thermal cracking" phenomenon that originates from defects originally possessed by the glass itself. In order to reduce the risk of "thermal cracking," it is desirable to reflect the light along the shortest path possible, and it is desirable to reduce the unevenness in the height of the reflective structure. From this point of view, it is also possible to reduce such defects by causing changes in the reflective structure with periodicity.

It is preferable that the inclination of the convex slope be an angle of 45° or more in order not to impair the efficiency of solar reflection. If the inclination is too gentle, the light will be reflected once, as it would be on a flat surface, and it will be difficult to obtain retroreflection through multiple reflections.

In the optical body, the entire surface of the first optical layer may have the above-mentioned predetermined convex shape, or a portion of the surface of the first optical layer may have the above-mentioned predetermined convex shape. When a portion of the surface of the first optical layer has the above-mentioned predetermined convex shape, it is preferable that the above-mentioned predetermined convex shape is provided in a location where it is desired to reduce localized strong reflection in regular reflection.

One embodiment of the optical body of the present invention has been described in which only one-dimensionally arranged convex shapes are present on one surface of the first optical layer. However, another embodiment of the optical body of the present invention includes an embodiment in which one surface of the first optical layer is formed by a two-dimensional array in which two of the one-dimensional arrays are combined.
The two-dimensional array is configured by combining two of the one-dimensional arrays. The two-dimensional array is a two-dimensional array in which one one-dimensionally arranged convex shape is combined with another one-dimensionally arranged convex shape having an extension direction and angle different from that of the other one-dimensionally arranged convex shape. In this case, one or both of the one-dimensionally arranged convex shapes satisfy at least one of the following (1) to (4) described above.
(1) The height of each columnar protrusion varies in the extension direction.
(2) The top of each columnar protrusion meanders in a direction perpendicular to both the extension direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped protrusion and a cylindrical protrusion having a curved surface are adjacent to each other.

In a corner cube body, retroreflection is achieved by reflecting light three times on the reflective surface, but while corner cube bodies are prone to solar radiation absorption due to multiple reflections, in the case of an optical layer having only the one-dimensional arrangement or the convex shape of the two-dimensional arrangement, the number of reflections is reduced, making it possible to suppress solar radiation absorption.
In addition, in a corner cube, retroreflection is achieved by reflecting the light three times on the reflective surface, but with a corner cube, some of the light is reflected twice and leaks in a direction other than retroreflection, whereas in the case of only the one-dimensional array or the two-dimensional array, a shape that reflects the light further toward the sky is possible.

From the viewpoint of imparting design features to optical members, window materials, and the like, the first optical layer may have a property of absorbing light of a specific wavelength in the visible region within a range that does not impair transparency to visible light.
The design property, that is, the property of absorbing light of a specific wavelength in the visible region, can be imparted by, for example, incorporating a pigment into the first optical layer.
The pigment is preferably dispersed in a resin.
The pigment to be dispersed in the resin is not particularly limited and can be appropriately selected depending on the purpose. Examples of the pigment include inorganic pigments and organic pigments. However, it is preferable to use an inorganic pigment, which has high weather resistance.
The inorganic pigment is not particularly limited and can be appropriately selected depending on the purpose. Examples of the inorganic pigment include zircon gray (Co, Ni doped ZrSiO ₄ ), praseodymium yellow (Pr doped ZrSiO ₄ ), chrome titanium yellow (Cr, Sb doped TiO ₂ or Cr, W doped TiO ₂ ), chrome green (Cr ₂ O ₃ , etc.), peacock ((CoZn)O(AlCr) ₂ O ₃ ), Victoria green ((Al, Cr) ₂ O ₃ ), Prussian blue (CoO.Al ₂ O _{3.SiO 2} ), vanadium zirconium blue (V doped ZrSiO ₄ ), chrome tin pink (Cr doped CaO.SnO _{2.SiO 2} ), ceramic red (Mn doped Al ₂ O ₃ ), and salmon pink (Fe doped ZrSiO ₄ ).
The organic pigment is not particularly limited and can be appropriately selected depending on the purpose. Examples of the organic pigment include azo pigments and phthalocyanine pigments.

<<Material for First Optical Layer>>
Examples of the material for the first optical layer include resins such as thermoplastic resins, active energy ray curable resins, and thermosetting resins.
The first optical layer has, for example, transparency. The first optical layer is obtained, for example, by curing a resin composition. From the viewpoint of ease of production, it is preferable to use an energy ray curable resin cured by light or electron beams, or a thermosetting resin cured by heat, as the resin composition. As the energy ray curable resin, a photosensitive resin composition cured by light is preferable, and an ultraviolet ray curable resin composition cured by ultraviolet rays is most preferable. From the viewpoint of improving the adhesion between the first optical layer and the inorganic layer, it is preferable that the resin composition further contains a compound containing phosphoric acid, a compound containing succinic acid, and a compound containing butyrolactone. As the compound containing phosphoric acid, for example, a (meth)acrylate containing phosphoric acid, preferably a (meth)acrylic monomer or oligomer having phosphoric acid in a functional group can be used. As the compound containing succinic acid, for example, a (meth)acrylate containing succinic acid, preferably a (meth)acrylic monomer or oligomer having succinic acid in a functional group can be used. As the compound containing butyrolactone, for example, a (meth)acrylate containing butyrolactone, preferably a (meth)acrylic monomer or oligomer having butyrolactone as a functional group, can be used.

The ultraviolet-curable resin composition contains, for example, (meth)acrylate and a photopolymerization initiator. In addition, the ultraviolet-curable resin composition may further contain a light stabilizer, a flame retardant, a leveling agent, an antioxidant, and the like, as necessary.

As the (meth)acrylate, it is preferable to use a monomer and/or oligomer having two or more (meth)acryloyl groups. As the monomer and/or oligomer, for example, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, polyol (meth)acrylate, polyether (meth)acrylate, melamine (meth)acrylate, etc. can be used. Here, the (meth)acryloyl group means either an acryloyl group or a methacryloyl group. Here, the oligomer means a molecule having a molecular weight of 500 or more and 60,000 or less.

Examples of polyfunctional monomers that can be used in the ultraviolet-curable resin composition include ethanediol diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,14-tetradecanediol diacrylate, 1,15-pentadecanediol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, 2-butyl-2-ethylpropanediol diacrylate, ethylene oxide-modified bisphenol A diacrylate, and the like. Acrylate, polyethylene oxide modified bisphenol A diacrylate, polyethylene oxide modified hydrogenated bisphenol A diacrylate, propylene oxide modified bisphenol A diacrylate, polypropylene oxide modified bisphenol A diacrylate, hydroxypivalic acid ester neopentyl glycol ester diacrylate, caprolactone adduct of hydroxypivalic acid ester neopentyl glycol ester diacrylate, ethylene oxide modified isocyanuric acid diacrylate, pentaerythritol diacrylate monostearate, 1,6-hexanediol diglycidyl ether acrylic acid adduct, polyoxyethylene ether Bichlorohydrin-modified bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, tricyclodecane dimethanol dimethacrylate, trimethylolpropane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, polyethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, polypropylene oxide-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, ethylene oxide-modified isocyanuric acid triacrylate, ethylene oxide-modified glycerol triacrylate, polyethylene oxide Examples of such compounds include modified glycerol triacrylate, propylene oxide modified glycerol triacrylate, polypropylene oxide modified glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, caprolactone modified dipentaerythritol hexaacrylate, polycaprolactone modified dipentaerythritol hexaacrylate, dioxane glycol diacrylate, and caprolactone modified tris(acryloxyethyl)isocyanurate.

As the photopolymerization initiator, a material appropriately selected from known materials can be used. Examples of known materials include benzophenone derivatives, acetophenone derivatives, and anthraquinone derivatives, which can be used alone or in combination. The amount of the polymerization initiator is preferably 0.1% by mass or more and 10% by mass or less of the solid content. If it is less than 0.1% by mass, the photocurability decreases and it may not be suitable for industrial production. On the other hand, if it exceeds 10% by mass, the coating film tends to have an odor when the amount of irradiation light is small. Here, the solid content refers to all components that constitute the hard coat layer after curing. Specifically, for example, the solid content refers to (meth)acrylate and the photopolymerization initiator.

<Inorganic Layer>
The inorganic layer is a layer disposed on the surface of the first optical layer on the side having the convex shape.
The inorganic layer is preferably a reflective layer that reflects at least near infrared rays. Examples of the reflective layer include the following laminated films. An example of the reflective layer will be described later in detail.

The average thickness of the inorganic layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 20 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. If the average thickness is 20 μm or less, the optical path along which the transmitted light refracts is shortened, and it is possible to prevent the transmitted image from appearing distorted.

The method for forming the inorganic layer is not particularly limited and can be appropriately selected depending on the purpose. For example, sputtering, vapor deposition, dip coating, die coating, etc. can be used.

The type of the inorganic layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the inorganic layer include a laminated film, a transparent conductive layer, a functional layer, and a semi-transparent layer. These may be used alone or in combination of two or more types.

The inorganic layer is, for example, semi-permeable.
Here, the term "semi-transparent" refers to a reflecting layer having a transmittance of 5% to 70%, preferably 10% to 60%, and more preferably 15% to 55% at wavelengths of 500 nm to 1,000 nm. Also, the term "semi-transparent layer" refers to a reflecting layer having a transmittance of 5% to 70%, preferably 10% to 60%, and more preferably 15% to 55% at wavelengths of 500 nm to 1,000 nm.

<<Laminated Film>>
The laminated film is not particularly limited and can be appropriately selected depending on the purpose. Examples of the laminated film include (i) a laminated film obtained by alternately laminating a low refractive index layer and a high refractive index layer having different refractive indexes, and (ii) a laminated film obtained by alternately laminating a metal layer having a high reflectance in the infrared region and an optically transparent layer having a high refractive index in the visible region and functioning as an antireflection layer, or a transparent conductive layer.

- Metal layer -
The metal layer is made of a metal that has a high reflectance in the infrared region.
The metal having a high reflectance in the infrared region is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include simple substances such as Au, Ag, Cu, Al, Ni, Cr, Ti, Pd, Co, Si, Ta, W, Mo, and Ge, and alloys containing two or more of these simple substances. Among these, Ag-based, Cu-based, Al-based, Si-based, and Ge-based substances are preferred from the viewpoint of practicality.
The alloy is not particularly limited and can be appropriately selected depending on the purpose, but preferred are AlCu, AlTi, AlCr, AlCo, AlNdCu, AlMgSi, AgPdCu, AgPdTi, AgCuTi, AgPdCa, AgPdMg, AgPdFe, Ag, SiB, and the like.
In order to suppress corrosion of the metal layer, it is preferable to add a material such as Ti, Nd, etc. to the metal layer, particularly when Ag is used as the material for the metal layer, it is preferable to add the above-mentioned material.

-Optical transparent layer-
The optically transparent layer has a high refractive index in the visible region and functions as an anti-reflection layer.
The material for the optically transparent layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the material include high dielectric materials such as niobium oxide, tantalum oxide, and titanium oxide.

In order to prevent oxidation deterioration of the underlying metal when the optically transparent layer is formed, a thin buffer layer of Ti or the like having a thickness of about several nm may be provided at the interface of the optically transparent layer to be formed. Here, the buffer layer is a layer that oxidizes itself when the upper layer is formed, thereby suppressing oxidation of the underlying metal layer, etc.

<<Transparent conductive layer>>
The transparent conductive layer is a transparent conductive layer containing, as a main component, a conductive material that has transparency in the visible region.
The transparent conductive layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the transparent conductive layer include transparent conductive substances such as tin oxide, zinc oxide, indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), antimony-doped tin oxide, and carbon nanotube-containing materials.
Furthermore, the transparent conductive layer may be a layer in which nanoparticles of the transparent conductive substance, nanoparticles of a conductive material such as a metal, nanorods, or nanowires are dispersed in a resin at a high concentration.

<<Functional layer>>
The functional layer is a layer containing as its main component a chromic material whose reflectivity or the like is reversibly changed in response to an external stimulus.
The chromic material is a material that reversibly changes its structure in response to an external stimulus such as heat, light, or an invading molecule.
The chromic material is not particularly limited and can be appropriately selected depending on the purpose. Examples of the chromic material include photochromic materials, thermochromic materials, gaschromic materials, and electrochromic materials.

The photochromic material is a material that reversibly changes its structure due to the action of light.
The photochromic material is a material whose physical properties, such as reflectance and color, can be reversibly changed by irradiation with light, such as ultraviolet light.
The photochromic material is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include transition metal oxides such as TiO ₂ doped with Cr, Fe, Ni, etc., WO ₃ , MoO ₃ , and Nb ₂ O _5. Furthermore, wavelength selectivity can be improved by laminating these layers with layers having different refractive indices.

The thermochromic material is a material that reversibly changes its structure due to the action of heat.
The thermochromic material is capable of reversibly changing various physical properties, such as reflectance and color, upon heating.
The thermochromic material is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include VO ₂ , etc. In addition, elements such as W, Mo, and F can be added for the purpose of controlling the transition temperature and transition curve.
Alternatively, a laminated structure may be used in which a thin film mainly made of a thermochromic material such as _VO2 is sandwiched between anti-reflection layers mainly made of a high refractive index material such as _TiO2 or ITO.

Alternatively, a photonic lattice such as a cholesteric liquid crystal can be used. The cholesteric liquid crystal can selectively reflect light of a wavelength according to the layer spacing, and since this layer spacing changes with temperature, physical properties such as reflectance and color can be reversibly changed by heating. In this case, it is also possible to widen the reflection band by using several cholesteric liquid crystal layers with different layer spacings.

Electrochromic materials are materials whose various physical properties, such as reflectance and color, can be reversibly changed by the application of electricity.
As the electrochromic material, for example, a material that reversibly changes its structure by application of a voltage can be used. Specific examples of the electrochromic material are not particularly limited and can be appropriately selected depending on the purpose, and include, for example, a reflective photochromic material whose reflection characteristics change by doping or dedoping with protons or the like.
Specifically, the reflective photochromic material is a material whose optical properties can be controlled to a transparent state, a mirror state, and/or an intermediate state by an external stimulus. The reflective photochromic material is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include an alloy material of magnesium and nickel, an alloy material mainly composed of an alloy material of magnesium and titanium, _WO3 , and a material in which needle-like crystals having selective reflectivity are enclosed in a microcapsule.

The specific configuration of the functional layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the functional layer include (i) _a configuration in which the above-mentioned alloy layer, a catalyst layer containing Pd or the like, a thin buffer layer such as Al, an electrolyte layer such as _Ta2O5 , an ion storage layer containing protons such as _WO3 , and a transparent conductive layer are laminated on the second optical layer, and (ii) a configuration in which a transparent conductive layer, an electrolyte layer, an electrochromic layer such as _WO3 , and a transparent conductive layer are laminated on the second optical layer.
In these configurations, by applying a voltage between the transparent conductive layer and the counter electrode, the protons contained in the electrolyte layer are doped or dedoped into the alloy layer. This changes the transmittance of the alloy layer. In addition, in order to improve wavelength selectivity, it is desirable to laminate the electrochromic material with a high refractive index material such as _TiO2 or ITO.
Another example of the configuration is a configuration in which a transparent conductive layer, an optically transparent layer in which microcapsules are dispersed, and a transparent electrode are laminated on the second optical layer. In this configuration, the needle-like crystals in the microcapsules can be oriented to a transparent state by applying a voltage between the two transparent electrodes, and the needle-like crystals can be oriented in all directions by removing the voltage to enter a wavelength selective reflection state.

<<Semi-transparent layer>>
The semi-transparent layer is, for example, made of a single metal layer or multiple metal layers and has semi-transparency.
The material for the metal layer is not particularly limited and can be appropriately selected depending on the purpose. For example, the same materials as those for the metal layer of the laminated film described above can be used.

<Second Optical Layer>
The second optical layer is a layer disposed on the inorganic layer side such that the convex shape is embedded therein.
The second optical layer, for example, protects the inorganic layer.
Examples of the material for the second optical layer include the materials exemplified in the description of the first optical layer.

Of the two main surfaces of the second optical layer, for example, one surface is smooth and the other surface is concave. The convex shape of the first optical layer and the concave shape of the second optical layer are in a relationship where the concave and convex shapes are inverted relative to each other.

The optical body is, for example, an optical film.

The optical body has transparency. The transparency is preferably within the range of the transmitted image clarity described later. The refractive index difference between the first optical layer and the second optical layer is preferably 0.010 or less, more preferably 0.008 or less, and even more preferably 0.005 or less. If the refractive index difference exceeds 0.010, the transmitted image tends to look blurred. If the refractive index difference is in the range of more than 0.008 and less than 0.010, it depends on the brightness of the outside, but there is no problem in daily life. If the refractive index difference is in the range of more than 0.005 and less than 0.008, the diffraction pattern is noticeable only for very bright objects such as light sources, but the outside scenery can be seen clearly. If the refractive index difference is 0.005 or less, the diffraction pattern is hardly noticeable. Of the first optical layer and the second optical layer, the optical layer that is to be bonded to a window material or the like may be mainly composed of an adhesive. With this configuration, the optical body can be bonded to a window material or the like by the first optical layer or the second optical layer mainly composed of an adhesive. In addition, when using such a configuration, it is preferable that the refractive index difference of the adhesive is within the above range.

It is preferable that the first optical layer and the second optical layer have the same optical properties such as refractive index. More specifically, it is preferable that the first optical layer and the second optical layer are made of the same material that has transparency in the visible region. By constructing the first optical layer and the second optical layer from the same material, the refractive index of both layers becomes equal, so that the transparency of visible light can be improved. However, even if the same material is used as the starting source, the refractive index of the layer that is finally generated may differ depending on the curing conditions in the film formation process, so care must be taken. In contrast, if the first optical layer and the second optical layer are constructed from different materials, the refractive index of both layers differs, so that light refracts at the inorganic layer (e.g., wavelength selective reflection layer) as a boundary, and the transmitted image tends to become blurred. In particular, when an object close to a point light source such as a distant electric light is observed, a diffraction pattern tends to be observed prominently. In addition, an additive may be mixed into the first optical layer and/or the second optical layer in order to adjust the value of the refractive index.

The first optical layer and the second optical layer are preferably transparent in the visible range. Here, there are two definitions of transparency: no light absorption and no light scattering. Generally, when transparency is used, it may refer to only the former, but it is preferable that the optical body has both. The retroreflectors currently used are intended to visually recognize the reflected light of road signs, night workers' clothes, etc., so even if they have scattering properties, if they are in close contact with the underlying reflector, the reflected light can be visually recognized. For example, even if an anti-glare treatment having scattering properties is applied to the front surface of an image display device in order to provide anti-glare properties, the image can be visually recognized, which is the same principle. However, one embodiment of the optical body is characterized in that it transmits light other than the specific wavelength that is directional reflected, and is adhered to a transparent body that mainly transmits this transmitted wavelength, and the transmitted light is observed, so it is preferable that there is no light scattering. However, depending on the application, it is also possible to intentionally give the second optical layer scattering properties.

The optical body is preferably used by being attached to a rigid body (e.g., a window material) that is mainly transparent to light other than the specific wavelength that has been transmitted, via an adhesive or the like. Examples of window materials include architectural window materials for high-rise buildings and houses, and window materials for vehicles. When the optical body is applied to architectural window materials, it is preferable to apply the optical film to window materials that are particularly arranged in any direction between east, south, and west (e.g., southeast to southwest). This is because applying the optical body to window materials in such positions can more effectively reflect heat rays. The optical body can be used not only for single-layer window glass, but also for special glass such as double-glazed glass. In addition, the window material is not limited to glass, and may be made of a polymer material having transparency. It is preferable that the optical layer has transparency in the visible range. This is because, when the optical body is attached to a window material such as window glass, it transmits visible light and ensures sunlight. In addition, the surface to be attached can be used not only on the inner surface of the glass, but also on the outer surface.

The optical body can be used in combination with other heat-ray-cutting films, and for example, a light-absorbing coating can be provided at the interface between air and the optical body (i.e., the outermost surface of the optical body). The optical body can also be used in combination with a hard coat layer, an ultraviolet-cutting layer, a surface anti-reflection layer, etc. When using these functional layers in combination, it is preferable to provide these functional layers at the interface between the optical body and air. However, since the ultraviolet-cutting layer needs to be placed on the sun side of the optical body, it is preferable to provide an ultraviolet-cutting layer between the window glass surface and the optical body, especially when used for interior application on the window glass surface inside the room. In this case, an ultraviolet absorbing agent may be kneaded into the bonding layer between the window glass surface and the body.

The optical body may be colored to impart design features depending on the application of the optical body. When imparting design features in this way, it is preferable that the optical layer is configured to absorb only light of a specific wavelength band without impairing transparency.

Here, an example of the optical body of the present invention will be described with reference to the drawings.
Fig. 12 is a cross-sectional view of an example of the optical body according to the first embodiment of the present invention. The optical body in Fig. 12 has the first optical layer 11 shown in Figs. 4A and 4B.
In FIG. 12 , optical body 10 comprises a first optical layer 11 having a convex surface, an inorganic layer 12 arranged on the surface of first optical layer 11 having the convex shape, a second optical layer 13 arranged on the inorganic layer 12 side so that the convex shape is buried, and a first substrate 14 arranged on the surface facing the surface of first optical layer 11 having the convex shape.

<Wavelength selective reflectivity>
13A and 13B are cross-sectional views for explaining an example of the function of the optical body, in which the shape of the convex portion is a prism shape with an inclination angle of 45° is taken as an example.
As shown in FIG. 13A , of the sunlight incident on this optical body 10, a portion of the light _L1 that is reflected into the sky is directionally reflected in the sky direction approximately the same as the incident direction, whereas light _L2 that is not reflected into the sky is transmitted through the optical body 10.
13A, the light that is incident on the optical body 10 and reflected by the reflective film surface of the inorganic layer 12 (wavelength-selective reflective layer) is separated into light _L1 that is reflected into the sky and light _L2 that is not reflected into the sky in a ratio according to the angle of incidence. Then, the light _L2 that is not reflected into the sky is totally reflected at the interface between the second optical layer 13 and the air, and is finally reflected in a direction different from the incident direction.
When the incident angle of light is α, the refractive index of the second optical layer 13 is n, and the reflectance of the wavelength selective reflection layer is R, the ratio x of the light _L1 reflected into the sky to the total incident component is expressed by the following formula (1).
x = (sin(45-α') + cos(45-α') / tan(45 + α')) / (sin(45-α') + cos(45-α')) × ^R2 ... (1)
Here, α'=sin ⁻¹ (sin α/n)
When the proportion of the light _L1 that is not reflected into the sky increases, the proportion of the incident light that is reflected into the sky decreases. In order to improve the proportion of the light that is reflected into the sky, it is effective to devise a shape of the wavelength-selective reflective layer, that is, a convex shape of the first optical layer 11.

FIG. 14 is a perspective view showing the relationship between the incident light incident on the optical body 10 having wavelength selective reflectivity and the reflected light reflected by the optical body 10. The optical body 10 has an incident surface S1 on which the light L is incident. The optical body 10 selectively reflects the light _L1 of a specific wavelength band out of the light L incident on the incident surface S1 at an incident angle (θ, φ) in a direction other than the regular reflection (-θ, φ+180°), while transmitting the light _L2 other than the specific wavelength band. The optical body 10 is also transparent to light other than the specific wavelength band. The transparency is preferably within the range of the transmitted image clarity described later. Here, θ: the angle between the perpendicular line _l1 to the incident surface S1 and the incident light L or the reflected light _L1 (hereinafter, "θ" may be referred to as the vertical angle). φ: the angle between a specific straight line _l2 in the incident surface S1 and the component of the incident light L or the reflected light _L1 projected onto the incident surface S1 (hereinafter, "φ" may be referred to as the azimuth angle). Here, the specific straight line _l2 in the incident surface is an axis where the reflection intensity in the φ direction is maximum when the incident angle (θ, φ) is fixed and the optical body 10 is rotated around the perpendicular line _l1 to the incident surface S1 of the optical body 10. However, if there are multiple axes (directions) where the reflection intensity is maximum, one of them is selected as the straight line _l2 . Note that the angle θ rotated clockwise with the perpendicular line _l1 as the reference is "+θ", and the angle θ rotated counterclockwise is "-θ". The angle φ rotated clockwise with the straight line _l2 as the reference is "+φ", and the angle φ rotated counterclockwise is "-φ".

The light in the specific wavelength band that is selectively directionally reflected and the specific light that is transmitted vary depending on the application of the optical body 10. For example, when the optical body 10 is applied to a window material as an external support, it is preferable that the light in the specific wavelength band that is selectively directionally reflected is near-infrared light, and the light in the specific wavelength band that is transmitted is visible light. Specifically, it is preferable that the light in the specific wavelength band that is selectively directionally reflected is mainly near-infrared light in the wavelength band of 780 nm to 2100 nm. By reflecting near-infrared light, when the optical body is attached to a window material such as a glass window, it is possible to suppress the temperature rise inside the building. Therefore, it is possible to reduce the cooling load and save energy. Here, directional reflection means that the reflected light intensity in a certain direction other than specular reflection is stronger than the specular reflected light intensity and is sufficiently stronger than the diffuse reflection intensity that has no directionality. Here, reflection indicates that the reflectance in a specific wavelength band, for example, in the near-infrared region, is preferably 30% or more, more preferably 50% or more, and even more preferably 80% or more. Transmitting means that the transmittance in a specific wavelength band, for example the visible light range, is preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more.

In the optical body 10 having wavelength selective reflectivity, it is preferable that the directional reflection direction φo is -90° or more and 90° or less. This is because, when the optical body 10 is attached to an external support, light of a specific wavelength band among light incident from the sky can be returned to the sky. When there are no tall buildings in the vicinity, the optical body 10 in this range is useful. In addition, it is preferable that the directional reflection direction is near (θ, -φ). Near refers to a deviation within a range of preferably 5 degrees, more preferably 3 degrees, and even more preferably 2 degrees from (θ, -φ). By setting it in this range, when the optical body 10 is attached to an external support, light of a specific wavelength band among light incident from the sky above buildings of similar height can be efficiently returned to the sky above other buildings. In order to realize such directional reflection, it is preferable to use a three-dimensional structure such as, for example, a part of a sphere or hyperboloid, a triangular pyramid, a square pyramid, or a cone. Light incident from the (θ, φ) direction (-90°<φ<90°) can be reflected in the (θo, φo) direction (0°<θo<90°, -90°<φo<90°) based on the shape. Alternatively, it is preferable to make it a columnar body extending in one direction. Light incident from the (θ, φ) direction (-90°<φ<90°) can be reflected in the (θo, -φ) direction (0°<θo<90°) based on the inclination angle of the columnar body. Therefore, when the heights of the buildings are about the same, it is possible to reflect (φ, θ) incident light in the (φ0, -θ) direction. In the present invention, when the building height is higher than the building on which the solar radiation is incident, or when the building is a building on which reflected light is incident in the vicinity, it is possible to mitigate the local reflection of solar radiation by combining the elements of the present invention.

In the optical body 10 having wavelength selective reflectivity, it is preferable that the directional reflection of light in a specific wavelength band is in the vicinity of the retroreflection direction, that is, the reflection direction of light in a specific wavelength band with respect to light incident on the incident surface S1 at an incident angle (θ, φ) is in the vicinity of (θ, φ). This is because, when the optical body 10 is attached to an external support, light in a specific wavelength band among light incident from the sky can be returned to the sky. Here, the vicinity is preferably within 5 degrees, more preferably within 3 degrees, and even more preferably within 2 degrees. By setting it in this range, when the optical body 10 is attached to an external support, light in a specific wavelength band among light incident from the sky can be efficiently returned to the sky. Therefore, when the heights of the buildings are about the same, it is possible to efficiently reflect light into the sky by changing the (φ, θ) incidence to (φ0, -θ). In the present invention, when the building height is higher than the building on which sunlight shines, or when the building is a building on which reflected light shines in the vicinity, it is possible to mitigate local reflection of sunlight by combining the elements of the present invention. Also, when the infrared light emitting unit and the light receiving unit are adjacent, such as in an infrared sensor or infrared imaging, the retroreflective direction must be the same as the incident direction, but if there is no need to sense from a specific direction, it does not have to be strictly the same direction.

<Transmitted image clarity>
In the optical body, the value of the transmitted image clarity for the wavelength band in which the optical body is transparent when a 2.0 mm optical comb is used is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 60% or more, and more preferably 75% or more.
Furthermore, in the optical body, the value of the transmitted image clarity for the wavelength band having transparency when a 0.5 mm optical comb is used is not particularly limited and can be appropriately selected according to the purpose, but is preferably 60% or more, more preferably 75% or more. If the transmitted image clarity value is 60% or more but less than 75%, the diffraction pattern is noticeable only for very bright objects such as light sources, but the outside scenery can be clearly seen. If the transmitted image clarity value is 75% or more, the diffraction pattern is hardly noticeable.
Here, the value of transmitted image clarity is measured using a Suga Test Instruments ICM-1T in accordance with JIS K-7374: 2007. However, when the wavelength to be transmitted is different from the wavelength of the D65 light source, it is preferable to perform the measurement after calibration using a filter of the wavelength to be transmitted.

<Method of Manufacturing Optical Body>
An example of a method for manufacturing an optical body according to an embodiment of the present invention will be described below with reference to Figures 15A to 15, 16A to 16C, and 17A to 17D. It should be noted that, in consideration of productivity, it is preferable that some or all of the manufacturing process described below is performed by roll-to-roll. However, this does not include the process of making a mold.

The manufacturing example here is an example of manufacturing an optical body having a first optical layer 11 shown in FIG. 4A and FIG. 4B.
First, as shown in FIG. 15A, a master 15 having the same convex shape as the convex shape of the first optical layer 11, or a mold (replica) having an inverted shape of the master 15, is formed by, for example, bit processing or laser processing. The method for producing the master 15 is as described with reference to FIG. 4C and FIG. 4D. Next, as shown in FIG. 15B, the convex shape of the master 15 is transferred to a film-like resin material by, for example, melt extrusion or transfer. Examples of the transfer method include a method in which a photocurable resin composition is poured into a mold and cured by irradiating it with energy rays, a method in which heat or pressure is applied to a resin to transfer the shape, or a method in which a resin film is supplied from a roll and the shape of the mold is transferred while applying heat (lamination transfer method). As a result, a first optical layer 11 having a convex shape on one main surface is formed as shown in FIG. 15C.

Also, as shown in FIG. 15C, the first optical layer 11 may be formed on the first substrate 14. In this case, for example, a method is used in which the film-like first substrate 14 is supplied from a roll, the photocurable resin composition is applied onto the first substrate 14, and then the substrate is pressed against a mold to transfer the shape of the mold, and the photocurable resin composition is cured by irradiating it with energy rays such as ultraviolet rays.

Next, as shown in FIG. 16A, a wavelength selective reflective layer (functional layer) is formed as an inorganic layer 12 on one main surface of the first optical layer 11. The method of forming the wavelength selective reflective layer as the inorganic layer 12 is not particularly limited and can be appropriately selected depending on the purpose. For example, sputtering, vapor deposition, CVD (Chemical Vapor Deposition), dip coating, die coating, wet coating, spray coating, etc. can be mentioned, and it is preferable to appropriately select from these film formation methods depending on the shape of the convex shape. Next, as shown in FIG. 16B, an annealing process 150 is performed on the wavelength selective reflective layer as the inorganic layer 12 as necessary. The temperature of the annealing process is, for example, in the range of 100° C. to 250° C.

Next, as shown in FIG. 16C, a photocurable resin composition 13A is applied onto the wavelength selective reflection layer serving as the inorganic layer 12.
Next, as shown in FIG. 17A, a photocurable resin composition 13A is spread to a predetermined thickness using a coater or the like to fill in the convex shapes, thereby forming a laminate.
Next, as shown in FIG. 17B, the photocurable resin composition 13A is cured by, for example, energy rays 160, and pressure 170 is applied to the laminate. The energy rays are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include electron beams, ultraviolet rays, visible light, gamma rays, and electron beams. Among these, ultraviolet rays are preferred from the viewpoint of production facilities. The cumulative irradiation amount is not particularly limited and can be appropriately selected in consideration of the curing characteristics of the resin, and the suppression of yellowing of the resin and the first substrate 14. The pressure applied to the laminate is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.01 MPa or more and 1 MPa or less. If the pressure applied to the laminate is less than 0.01 MPa, problems will occur in the running properties of the film, and if it exceeds 1 MPa, it will be necessary to use a metal roll as a nip roll, which is likely to cause pressure unevenness.
As a result of the above, as shown in FIG. 17C, the second optical layer 13 is formed on the wavelength selective reflection layer serving as the inorganic layer 12, and the optical body 10 is obtained.
Furthermore, in the optical body of the present invention, a second substrate may be disposed on the side of the second optical layer 13 opposite to the inorganic layer 12 side.
The flatness of the surface of the second optical layer 13 opposite to the inorganic layer 12 side depends on the flatness of the coater head and the like, and the thickness of the resin (how the unevenness is filled in).

Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
The effect of changing the convex shape of the optical body on the upward reflection directivity was confirmed by simulation.

In Example 1, an optical body in which the height of the triangular cross section in the convex shape changes continuously in the extension direction (an optical body satisfying the above (1)) was evaluated.
The convex shape has the following characteristics.
Average pitch (distance between valleys of adjacent structures): 67 μm
Average height (AH): 31 μm
Height amplitude (A): 5 μm
Amplitude type: sine wave Sine wave period (Pe): 800 μm
Maximum apex inclination angle in extension direction (E): 1.1 deg
Phase difference (ΔPh) between adjacent structures: 1/2 period

In order to confirm the effect of reflection due to the shape of the reflecting surface, a simulation was performed using the ray tracing method.
The light rays were quasi-parallel, and a sufficient number of light rays were irradiated from the light source towards the reflecting surface using the Monte Carlo method (the structure of the reflector was the same as the real thing, with the reflecting surface embedded in resin).
In the simulation, the upward reflectance of near-infrared light was calculated at a vertical angle (θ) of 20 deg from the normal direction to the surface of the measurement sample. The azimuth angle (φ) of incidence to the sample was set to φ=0 deg.
The reflected light was evaluated by calculating the light intensity at every 1 degree in both the vertical angle and the azimuth angle, in the same manner as in the Mini Diff used in the actual measurements described below, and comparing the results as follows.

<Upward reflection>
From the distribution of reflection intensity obtained by simulation using the ray tracing method, the upward reflection components reflected toward the sky side of the horizontal line containing the normal to the light incidence direction surface of the test model were counted, and the relative value % was calculated as the relative value of the upward reflection when the numerical result of the upward reflection component in the triangular prism of Comparative Example 1 described below was set to 100%.
The degree to which the upward reflection performance was not impaired was evaluated based on this relative value of upward reflection.

<Local reflection>
From the distribution of reflection intensity obtained by simulation using the ray tracing method, the highest intensity value excluding specular reflection (peak reflection intensity) was read, and the relative value % was calculated as the local reflection intensity ratio, assuming the result of the highest intensity value (peak reflection intensity) excluding specular reflection of the triangular prism in Comparative Example 1 described below as 100%.
The effect of suppressing local reflection was evaluated based on the relative value of the highest intensity excluding this specular reflection.

The convex shape of Example 1 is shown in Table 1-1. The evaluation results of Example 1 are shown in Table 1-2.

The state of local reflexes was evaluated according to the following criteria.
〔Evaluation criteria〕
・X: Light incident at an angle on the surface of the optical body is reflected in a straight line from the reflecting part, resulting in a localized bright spot. ・○: Light incident at an angle on the surface of the optical body is reflected in a non-linear manner from the reflecting part, resulting in a band-like bright spot or being divided into multiple spots, reducing the localized bright spot.

(Examples 2 to 13, Comparative Examples 1 and 2)
In Example 1, evaluation was performed in the same manner as in Example 1, except that the shape of the convex portion was changed as shown in Table 1-1. The results are shown in Table 1-2. Note that, in the convex shape of Example 13, as shown in FIG. 9A, a triangular prism-shaped convex portion and a columnar convex portion having a curved surface are adjacent to each other.

The above results are summarized in graphs and shown in FIGS.
FIG. 20 is a graph showing the relationship between the amplitude and the relative value of the reflected light intensity (local reflection intensity ratio).
FIG. 21 is a graph showing the relationship between the amplitude/period and the relative value of the reflected light intensity (local reflection intensity ratio).
FIG. 22 is a graph showing the relationship between the maximum change angle and the relative value of the reflected light intensity (local reflection intensity ratio).
FIG. 23 is a graph showing the relationship between the amplitude and the relative value of the upward reflection component.
FIG. 24 is a graph showing the relationship between the amplitude/period and the relative value of the upward reflection component.
FIG. 25 is a graph showing the relationship between the maximum change angle and the relative value of the upward reflection component.
20 to 22, it was confirmed that, compared to the triangular prism of Comparative Example 1, the effect of suppressing local reflection was high when there was amplitude change in height (corresponding to the above-mentioned aspect (1)), in-plane meandering (corresponding to the above-mentioned aspect (2)), and a combination of a triangular prism and a curved surface (corresponding to the above-mentioned aspect (4)).
In particular, it was confirmed that the presence of amplitude variation in height (corresponding to aspect (1) above) is more effective in suppressing local reflections than an in-plane meandering (corresponding to aspect (2) above) and a combination of a triangular prism and a curved surface (corresponding to aspect (4) above).
23 to 25, it was confirmed that Comparative Example 2, which has only a curved shape, has low upward reflection, and that by combining the triangular prism and curved shape of Example 13, it is possible to suppress local reflection while maintaining upward reflection. This is thought to be because the curved shape of Comparative Example 2 does not cause multiple reflections, which are necessary for light to travel upward.

(Example 14-1)
<Preparation of Optical Body>
In order to create a structure whose height continuously varies in the direction in which the triangular cross section shown in Fig. 5A extends, the master was processed so that the height varies in the extension direction of the triangular columnar structures as shown in Fig. 5D. The optical body to be created is an optical body that satisfies the above (1).

Master processing specifications Average feature spacing (distance between valleys of adjacent structures): 67 μm
Average profile height (AH): 31 μm
Cross-section base angle - D1: 35 deg
Cross-section base angle-D2: 55 deg
Height amplitude in extension direction (A): 10.5 μm
Height modulation in extension direction: sine wave Sine wave period (Pe): 800 μm
Phase difference (ΔPh) between adjacent structures: 1/2 period (processing to give a phase of 1/2 period to the height modulation of adjacent structures so that when the height of a structure is at its highest, the height of the adjacent structure is at its lowest)

Using this processed master, a photocurable resin composition (resin refractive index after curing: 1.52) was applied to a PET substrate (manufactured by Toray, thickness 75 μm) by a transfer method, and cured by irradiating with ultraviolet light to form a first optical layer having structures on its surface whose heights vary continuously in the direction in which the triangular cross section shown in FIG. 5A extends. The thickness after curing was 110 μm.

On the first optical layer formed, an inorganic layer having the following composition that reflects near-infrared rays was formed by vacuum sputtering. A photocurable resin composition (resin refractive index after curing: 1.52) was applied onto the formed inorganic layer, and a second optical layer was formed by curing the composition by irradiating ultraviolet light onto a PET substrate (manufactured by Toray Industries, Inc., thickness 75 um). In this manner, an optical body was obtained. The thickness of the obtained optical body after curing was 205 μm.
The obtained optical body was subjected to the following tests and measurements, and the results are shown in Table 2-2.

<<Configuration of Inorganic Layer>>
(First optical layer)/ _Nb2O5 (36 _nm ) _/ AgPdCu (11 _nm )/ _{Al2O3- ZnO} (4 nm)/Nb2O5 (80 _nm )/AgPdCu (11 nm)/Al2O3-ZnO ( ₄ nm)/ _Nb2O5 ( ₃₆ nm)/ _{Al2O3 -} ZnO (4 nm)/(Second optical layer)
Here, for the deposition of AgPdCu, an alloy target containing Ag/Pd/Cu=98.1% by mass/0.9% by mass/1.0% by mass was used.
A ceramic target in which 2 mass% of Al ₂ O ₃ was added to ZnO [ZnO:Al ₂ O ₃ = 100:2 (mass ratio)] was used to form the Al ₂ O ₃ -ZnO film, and Nb ₂ O ₅ was used to form the Nb ₂ O ₅ film. Here, the thickness of each layer is indicated as the thickness when the film was formed on a featureless flat surface.

<Visible light transmittance, visible light reflectance, shading coefficient>
The test was carried out in accordance with JIS A 5759. Specifically, the optical body was attached to a float glass having a thickness of 3 mm with a commercially available highly transparent adhesive material, and the optical body was measured with a spectrophotometer (UH4150) manufactured by Hitachi High-Tech Science Corporation.
From the obtained spectral transmittance and reflectance values, the visible light transmittance, visible light reflectance and shading coefficient were calculated in accordance with JIS A5759.
The state in which the optical body is attached to the float glass using an adhesive is shown in Fig. 26. In Fig. 26, reference numeral 110 denotes the second base material, reference numeral 111 denotes the float glass, and reference numeral 112 denotes the adhesive. Reference numeral D1 denotes the cross-sectional base angle -D1, and reference numeral D2 denotes the cross-sectional base angle -D2.

<Haze value>
The above-mentioned sample was used to carry out a test in accordance with JIS K 7136. Specifically, the optical body was attached to a float glass having a thickness of 3 mm with a commercially available transparent adhesive material, and the haze was measured with a haze meter (NDH7000) manufactured by Nippon Denshoku Industries Co., Ltd.

<Near infrared upward reflectance>
Using the sample used in the optical measurement, the upward reflectance of near-infrared light at a vertical angle (θ) of 60 deg from the normal direction to the surface of the measurement sample was measured in accordance with 4.4 Directional Reflection Performance (http://www.env.go.jp/policy/etv/pdf/list/h27/051-1506a.pdf) described in the Ministry of the Environment's FY2015 Environmental Technology Demonstration Project Verification Number: 051-1506. The azimuth angle (φ) of the incident light to the sample was set to the direction in which the upward reflection performance of the sample was most efficiently expressed (for the vertical azimuth angle (θ), see, for example, FIG. 26).
The obtained spectral reflectance value was multiplied by a weighting factor in accordance with JIS A5759 to calculate the upward reflection component in the near infrared region (780 to 2500 nm) as the upward reflectance.

<Upward reflection directionality>
The reflection directivity was measured using MiniDiff manufactured by Light Tec Corporation, and the effect of suppressing local reflection was evaluated.
Since the MiniDiff manufactured by Light Tec is an evaluation device using a visible light source, it is difficult to measure the reflection distribution of near-infrared rays. Therefore, the inorganic layer that reflects near-infrared rays in Example 14-1 was changed to a film of Ag 30 nm. In addition, the size of the 3 mm thick float glass used in the optical measurement described above was changed to □10 cm x 10 cm. Other than that, samples were prepared in the same manner and used for measurement.
This method makes it possible to measure the reflection distribution using visible light, and to evaluate the reflection directivity.
In the measurement, the upward reflectance of near-infrared rays was measured at a vertical angle (θ) of 20 deg from the normal direction to the surface of the measurement sample. The azimuth angle (φ) of incidence with respect to the sample was set to φ=0 deg, which is a direction rotated 90 deg from the ridge direction of the triangular prism of the first optical layer, as the direction in which the upward reflection performance of the sample is most efficiently exhibited, and to φ15 deg, which is a direction further rotated 15 deg.
From the distribution of reflection intensity, the highest intensity value excluding specular reflection (peak reflection intensity) was read, and the relative value % was calculated as the local reflection intensity ratio, assuming the result of the highest intensity value excluding specular reflection (peak reflection intensity) of the triangular prism in Comparative Example 3-1 described below as 100%.
The effect of suppressing local reflection was evaluated based on the relative value of the highest intensity excluding this specular reflection.

<Local reflection state>
The state of distribution of reflected light obtained when measuring reflection directivity using the above-mentioned MiniDiff manufactured by Light Tec Corporation was evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
・X: Light incident at an angle on the surface of the optical body is reflected in a straight line from the reflecting part, resulting in a localized bright spot. ・○: Light incident at an angle on the surface of the optical body is reflected in a non-linear manner from the reflecting part, resulting in a band-like bright spot or one that is divided into multiple spots, reducing the localized bright spot.

<Appearance evaluation of bright lines>
The optical body was attached to a piece of float glass measuring 15 cm×15 cm and 3 mm in thickness via an adhesive, and a small light source was irradiated from 15 cm above the optical body, and the appearance was observed.
The visibility of the bright lines was evaluated according to the following criteria.
〔Evaluation criteria〕
・×: A clear bright line is observed from the bright point of the light source to the edge of the float glass. ・〇: The bright line is very faint from the bright point of the light source to the edge of the float glass and is difficult to see.

(Examples 14-2 to 14-15)
In the evaluation of local reflection, the evaluation was performed in the same manner as in Example 14-1, except that the vertical angle (θ) and azimuth angle (φ) were as shown in Table 2-2. The results are shown in Table 2-2.

(Example 15-1)
An optical body was produced in the same manner as in Example 14-1, except that the master processing specifications were changed as follows, and evaluated in the same manner as in Example 14-1. The results are shown in Table 2-2.
Master processing specifications Average feature spacing (distance between valleys of adjacent structures): 67 μm
Average profile height (AH): 31 μm
Cross-section base angle - D1: 35 deg
Cross-section base angle-D2: 55 deg
Height amplitude in extension direction (A): 21 μm
Height modulation in extension direction: sine wave Sine wave period (Pe): 800 μm
Phase difference (ΔPh) between adjacent structures: 1/2 period (processing to give a phase of 1/2 period to the height modulation of adjacent structures so that when the height of a structure is at its highest, the height of the adjacent structure is at its lowest)

(Examples 15-2 to 15-15)
In the evaluation of local reflection, the evaluation was performed in the same manner as in Example 14-1, except that the vertical angle (θ) and azimuth angle (φ) were as shown in Table 2-2. The results are shown in Table 2-2.

(Comparative Example 3-1)
In Example 14-1, the master processing specifications were changed as follows, and the master was processed into a shape in which structures with extended triangular cross sections were arranged in parallel, as shown in Figure 3D. An optical body was produced in the same manner as in Example 14-1, and evaluated in the same manner.
Master processing specifications: Shape spacing (distance between valleys of adjacent structures): 67 μm
Shape height: 31 μm
Cross-section base angle - D1: 35 deg
Cross-section base angle-D2: 55 deg

(Comparative Examples 3-2 to 3-15)
In the evaluation of local reflection, the evaluation was performed in the same manner as in Example 14-1, except that the vertical angle (θ) and azimuth angle (φ) were as shown in Table 2-2. The results are shown in Table 2-2.

<Regarding the results obtained>
<<Visible light characteristics, solar radiation characteristics, near-infrared upward reflectance>>
In Examples 14-1 to 14-15 and Examples 15-1 to 15-15, similar performance to that of Comparative Examples 3-1 to 3-15 was obtained in terms of visible light transmittance, reflectance, haze value, shading coefficient, and near-infrared upward reflectance.

<<Reflection directivity (local reflection suppression)>>
In Comparative Examples 3-1 to 3-15, the reflected light was reflected along a local line without being scattered, whereas in Examples 14-1 to 14-15 and Examples 15-1 to 15-15, it was confirmed that local reflection was suppressed.
In addition, from the distribution of reflection intensity, the highest intensity value excluding specular reflection was read, and the result of the comparative example measured at the same azimuth angle and incident angle was set to 100%, and from the intensity ratio of local reflection based on the relative value of the reflection intensity at the highest intensity value excluding specular reflection in the optical body of the present invention, it can be seen that local reflection is suppressed in the optical body of the present invention.
In addition, it can be seen that the bright lines that occur when a light source is irradiated due to a regular structure are suppressed in the optical body of the present invention having a reflective structure whose height is modulated in the extension direction of the structure, compared to Comparative Examples 3-1 to 3-15.

The optical body of the present invention can be suitably used as a heat ray reflective film that is attached to window glass and retroreflects sunlight.

REFERENCE SIGNS LIST 10 Optical body 11 First optical layer 12 Inorganic layer 13 Second optical layer 14 First substrate

Claims (5)

a first optical layer having a convex surface on which a plurality of triangular prism -shaped protrusions extending in one direction are one-dimensionally arranged in one direction;
an inorganic layer disposed on the surface of the first optical layer on the side having the convex shape;
a second optical layer disposed on the inorganic layer side so that the convex shape is embedded in the second optical layer;
having
The convex shape of the heat ray reflecting optical body satisfies at least one of the following (1) and (2):
(1) In each triangular prism-shaped protrusion, the height changes in the extension direction , the amplitude is 15 μm or more and 40 μm or less, and the shift in the periodic change in height of adjacent triangular prism-shaped protrusions is 1/4 period or more and 3/4 period or less .
(2) In each triangular prism-shaped protrusion, the top meanders in a direction perpendicular to both the extension direction and the height direction of the protrusion , and the amplitude is 20 μm or more and 40 μm or less . The heat ray reflecting optical body according to claim 1, wherein the inorganic layer is a wavelength selective reflecting layer. The heat ray reflecting optical body according to claim 1, wherein the inorganic layer is semi-transparent. The heat ray reflecting optical body according to any one of claims 1 to 3, wherein the first optical layer and the second optical layer are transparent. The heat ray reflecting optical body according to any one of claims 1 to 3, which is attached to a window glass for use.