JP2023078245A - Heat ray reflection optical body - Google Patents

Abstract

To provide an optical body having a convex shape having a plurality of columnar projections extending in one direction and one-dimensionally arranged toward one direction, and capable of reducing local strong reflection in specular reflection.SOLUTION: An optical body includes: a first optical layer having a convex surface having a plurality of columnar projections extending in one direction and one-dimensionally arranged toward one direction; an inorganic layer arranged on the surface of the first optical layer on the side having the convex shape; and a second optical layer arranged so as to bury the convex shape on the inorganic layer side. The convex shape satisfies at least one of the following (1)-(4). (1) The height of each columnar projection changes in the extension direction; (2) the top part of each columnar projection meanders in a direction orthogonal to both the extension direction and the height direction of the projection; (3) the heights of columnar projections adjacent to each other are different; and (4) a triangle pole shaped projection is adjacent to a curved columnar projection.SELECTED DRAWING: Figure 4A

Description

The present invention relates to optical bodies.

2. Description of the Related Art In recent years, optical films are widely known for the purpose of imparting various effects such as absorption and reflection to incident light. This optical film has various configurations depending on the intended function. As one of them, there is one in which an uneven interface is formed inside and a thin film is formed on this interface. For example, Patent Document 1 discloses, as an optical film having the above configuration, a first substrate having an uneven surface in which a plurality of prisms are arranged one-dimensionally, a laminated film formed on the uneven surface, and the laminated film A retroreflective polarizer is disclosed comprising a second substrate formed thereon.

As an example of such an uneven shape of an optical film, a plurality of columnar protrusions extending in one direction are arranged one-dimensionally in one direction, as described in FIGS. 3A to 3C of Patent Document 2. It is a shape that is Here, the height of the columnar protrusions is the same at any position, and the distance between the tops of adjacent protrusions is the same at any position.

JP 2004-78234 A JP 2011-128512 A

The optical film having the above shape is disposed on a window glass, for example, as a heat ray reflective film that retroreflects sunlight, such that the one-dimensional arrangement direction is parallel to the horizontal direction.
At this time, light coming in from the sun, for example, incident from above in the southeast is reflected upward in the southwest. This reflected light is the sunlight that is the light source and is locally reflected, so in the case of the heat ray retroreflecting function, the heat ray is reflected. If there is a building in the straight direction of the reflected light, it will be exposed to heat rays and suffer heat damage.
In addition, when the reflected light is visible light, there is a risk of feeling glare and impairing the view from the window.
Therefore, the present situation is that an optical body is required to reduce local strong reflection in specular reflection.

The present invention is capable of reducing local strong reflection in specular reflection in an optical body having a convex shape in which a plurality of columnar convex portions extending in one direction are one-dimensionally arranged in one direction. An object of the present invention is to provide an optical body capable of

Means for solving the above problems are as follows. Namely
<1> A first optical layer having a convex surface in which a plurality of columnar convex portions 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 such that the convex shape is buried;
has
The optical body is characterized in that the convex shape satisfies at least one of the following (1) to (4).
(1) In each columnar protrusion, the height changes in the extending direction.
(2) In each columnar protrusion, the apex meanders in a direction perpendicular to both the extending direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped convex portion is adjacent to a columnar convex portion having a curved surface.
<2> The optical body according to <1>, wherein the inorganic layer is a wavelength selective reflection 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 are transparent.
<5> The optical body according to any one of <1> to <4>, which is used by being attached to a windowpane.

According to the present invention, in an optical body having a convex shape in which a plurality of columnar convex portions extending in one direction are one-dimensionally arranged in one direction, local strong reflection in specular reflection is reduced. It is possible to provide an optical body capable of

FIG. 1A is a diagram for explaining a state in which sunlight is reflected on a window to which an optical film having a heat ray retroreflecting structure shown in FIG. 3A is attached (No. 1). FIG. 1B is a diagram for explaining a state in which sunlight is reflected on the window to which the optical film having the heat ray retroreflecting structure shown in FIG. 3A is attached (No. 2). FIG. 2A is a diagram for explaining a state in which sunlight is reflected on the window to which the optical film having the heat ray retroreflecting structure shown in FIG. 4A is attached (No. 1). FIG. 2B is a diagram for explaining a state in which sunlight is reflected on the window to which the optical film having the heat ray retroreflecting structure shown in FIG. 4A is attached (Part 2). 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 the conventional example. FIG. 3C is a schematic diagram of a master and a cutting tool for manufacturing the first optical layer of FIGS. 3A and 3B. FIG. 3D is a perspective view of the master in FIG. 3C in a flat plate shape. FIG. 4A is a perspective view of an example first optical layer of an optical body of the present invention. FIG. 4B is a top view of an example 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 manufacturing the first optical layer of FIGS. 4A and 4B. FIG. 4D is a perspective view of the master in 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 manufacturing the first optical layer of FIGS. 5A and 5B. FIG. 5D is a perspective view of the master in 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 manufacturing the first optical layer of FIGS. 6A and 6B. FIG. 6D is a perspective view of the master in 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 layers of the optical body of the present invention. FIG. 7C is a schematic diagram of a master and a cutting tool for manufacturing the first optical layer of FIGS. 7A and 7B. FIG. 7D is a perspective view of the master in 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 manufacturing the first optical layer of FIGS. 8A and 8B. FIG. 8D is a perspective view of the master in 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 layers of the optical body of the present invention. FIG. 9C is a schematic diagram of a master and a cutting tool for manufacturing the first optical layer of FIGS. 9A and 9B. FIG. 9D is a perspective view of the master in FIG. 9C in a flat plate shape. FIG. 10A is a cross-sectional view for explaining the height of the convex portion of the first optical layer (No. 1). FIG. 10B is a cross-sectional view for explaining the height of the convex portion of the first optical layer (No. 2). FIG. 11A is a cross-sectional view for explaining the distance (pitch) between adjacent convex portions of the first optical layer (No. 1). FIG. 11B is a cross-sectional view for explaining the distance (pitch) between adjacent convex portions of the first optical layer (No. 2). 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 chart for explaining an example of a method for manufacturing an optical body according to an embodiment of the present invention (No. 1). FIG. 15B is a process diagram for explaining an example of the method for manufacturing an optical body according to one embodiment of the present invention (No. 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 (No. 3). FIG. 16A is a process diagram for explaining an example of a method for manufacturing an optical body according to an embodiment of the present invention (No. 4). FIG. 16B is a process diagram for explaining an example of the method for manufacturing an optical body according to one embodiment of the present invention (No. 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 (No. 6). FIG. 17A is a process diagram for explaining an example of a method for manufacturing an optical body according to an embodiment of the present invention (No. 7). FIG. 17B is a process drawing for explaining an example of a method for manufacturing an optical body according to an embodiment of the present invention (No. 8). FIG. 17C is a process diagram for explaining an example of the method for manufacturing an optical body according to one embodiment of the present invention (No. 9). FIG. 18A is a diagram for explaining the average height (AH), the amplitude (A), the period (Pe), and the tilt angle (E) that provides the maximum amount of change. FIG. 18B is a diagram for explaining the deviation (ΔPh) of periodic change. FIG. 19 is a diagram for explaining the amplitude (Ab), the period (Peb), the tilt angle (Eb) at which the maximum amount of change is obtained, and the deviation of the periodic change (ΔPhb). FIG. 20 is a graph showing the relationship between amplitude and relative value of reflected light intensity. FIG. 21 is a graph showing the relationship between amplitude/period and relative value of reflected light intensity. FIG. 22 is a graph showing the relationship between the maximum change angle and the relative value of 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 reflected 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 the 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 optionally other members.

A conventional optical film 100A having a convex shape in which a plurality of columnar convex portions extending in one direction are one-dimensionally arranged in one direction is applied to a window glass so that the one-dimensionally arranged direction is the horizontal direction. , the light entering the window 100 from the sun 101 is usually specularly reflected, and at the point where the light enters the window 100, a columnar array extending in one direction The direction is reflected to the sky side (FIGS. 1A and 1B).
In such cases, the sun's rays are locally reflected (FIGS. 1A and 1B). Therefore, if there is an adjacent building 102, the building 102 will be exposed to reflected light rays. Therefore, when the heat ray is reflected, the reflected heat ray irradiates a portion of the building 102 that is not normally penetrated by the sunlight or a portion where the sunlight is shining, thereby preventing heat damage. (Fig. 1A).

Therefore, as a result of intensive studies, the present inventors have found that, in an optical body, a convex shape in which a plurality of columnar convex portions extending in one direction are one-dimensionally arranged in one direction has uniformity. Specifically, in the optical body, a convex shape in which a plurality of columnar convex portions extending in one direction are one-dimensionally arranged in one direction is the following (1) to The inventors have found that by satisfying at least one of (4), local strong specular reflection can be reduced, and have completed the present invention.
(1) In each columnar protrusion, the height changes in the extending direction.
(2) In each columnar protrusion, the apex meanders in a direction perpendicular to both the extending direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped convex portion is adjacent to a columnar convex portion having a curved surface.

A plurality of columnar projections extending in one direction have a convex shape that is one-dimensionally arranged in one direction, and the convex shape satisfies at least one of the above (1) to (4). When the optical film 100B of the present invention is arranged on a window glass so that the one-dimensional arrangement direction is parallel to the horizontal direction, the light that enters the window 100 from the sun 101 is reflected in the window 100. At the insertion point, the light is reflected toward the sky around the direction in which the columns extending in one direction are arranged (FIGS. 2A and 2B).
In such cases, the sun's rays are usually strongly specularly reflected locally (FIGS. 1A and 1B). On the other hand, when the optical film 100B of the present invention is used, specular reflection is moderated locally (FIGS. 2A and 2B). Therefore, even if there is an adjacent building 102, the building 102 is less susceptible to heat damage.

A mode in which the convex shape satisfies at least one of the above (1) to (4) will be described together with an example of a manufacturing method.

First, the conventional first optical layer will be described.
FIG. 3A is a perspective view of a first optical layer 91 in a conventional example. 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 projections 91A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 3B, thick straight solid lines indicate the peaks of the columnar protrusions 91A, and dashed lines indicate the valleys between the columnar protrusions.
As shown in FIGS. 3A and 3B, in the conventional first optical layer 91, the height of the columnar protrusions 91A is the same at any position, and the distance between the tops of adjacent protrusions is is the same at any position.
The first optical layer 91 of FIGS. 3A and 3B is fabricated, for example, as follows.
The first optical layer 91 is produced by transferring the convex shape of a master on which the convex shape is formed.
As shown in FIG. 3C, the master 95 is roll-shaped, for example. While the master 95 is being rotated, a cutting tool 96 having a tip portion of a predetermined shape is applied to the master 95 so as to cut a predetermined depth, thereby cutting the master 95 . When the cutting of one round of the master 95 is completed, the cutting tool 96 is moved by a predetermined distance in the direction perpendicular to the rotation direction, and the 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 in a flat plate shape.
Alternatively, while rotating the roll-shaped master 95, a cutting tool 96 having a tip portion of a predetermined shape is applied to the master 95 so as to cut a predetermined depth, and when the master 95 is cut to a predetermined depth, cutting is performed in a spiral shape. By determining the number of rotations of the roll and the moving distance of the cutting tool, continuous machining is possible, and machining with improved machining efficiency is also possible.
The master 95 is pressed against an uncured resin sheet, or an uncured resin sheet is pressed against the master 95, the convex shape of the master 95 is transferred to the resin sheet, and the resin sheet is cured to obtain the first of optical layers can be obtained.

Next, one aspect 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 projections 11A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 4B, the thick linear solid lines indicate the tops of the columnar protrusions 11A, and the dashed lines indicate the valleys between the columnar protrusions.
As shown in FIGS. 4A and 4B, in the first optical layer 11 of one aspect of the present invention, the height of the columnar convex portions 11A changes continuously. Note that in the top view of FIG. 4B, both the top and the bottom are linear.
The first optical layer 11 in FIGS. 4A and 4B is produced, for example, as follows.
The first optical layer 11 is produced by transferring the convex shape of a master on which the convex shape is formed.
As shown in FIG. 4C, the master 15 is, for example, roll-shaped. While rotating the master 15, a cutting tool 16 having a tip portion of a predetermined shape is applied to the master 15 to cut the master 15. - 特許庁By vertically moving the cutting tool 16 during cutting, cut grooves with continuously different cutting depths can be obtained. When the cutting of one circumference of the master 15 is completed, the cutting tool 16 is moved by a predetermined distance in the direction perpendicular to the rotation direction, and the cutting of the master 15 is resumed. At this time, the cutting is performed so that the cutting tool 16 is vertically moved at the same timing as before. That is, in a plurality of cut grooves produced by cutting, the vertical movement timing 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 process, the master 15 having a convex shape in which the height of the columnar convex portion is continuously changed is obtained. By making the timing of the vertical movement the same, the apex of the columnar projection becomes linear when viewed from above. FIG. 4D is a perspective view of the master 15 in a flat plate shape.
The vertical movement of the cutting tool 16 can be performed by using driving means such as a piezo element or a solenoid actuator.
The master 15 is pressed against an uncured resin sheet, or an uncured resin sheet is pressed against the master 15, the convex shape of the master 15 is transferred to the resin sheet, and the resin sheet is cured to obtain the first of the optical layer 11 can be obtained.
Alternatively, instead of the above-described transfer method, a mold (replica) having a reversed shape is produced by transferring the convex shape of the master 15, and the mold is pressed against an uncured resin sheet to reproduce the master 15. The first optical layer 11 can also be obtained by copying the convex shape onto the resin sheet and curing the resin sheet.

Next, another aspect 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 arranged one-dimensionally in one direction.
In FIG. 5B, thick wavy solid lines indicate the peaks of the columnar protrusions 21A, and broken lines indicate the valleys between the columnar protrusions.
As shown in FIGS. 5A and 5B, in the first optical layer 21 of one aspect of the present invention, the height of the columnar protrusions 21A changes continuously. In addition, in the top view of FIG. 5B, the crest is meandering and the bottom is 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 the convex shape of a master on which the convex shape is formed.
As shown in FIG. 5C, the master 25 is, for example, roll-shaped. While rotating the master 25, a cutting tool 26 having a tip portion of a predetermined shape is applied to the master 25 to cut the master 25. - 特許庁By vertically moving the cutting tool 26 during cutting, cut grooves with continuously different cutting depths can be obtained. When the cutting of one round of the master disk 25 is completed, the cutting tool 26 is moved by a predetermined distance in the direction perpendicular to the rotation direction, and the cutting of the master disk 25 is resumed. At this time, the cutting is performed while vertically moving the cutting tool 26 so that the timing of the vertical movement is different from the previous one. That is, the timing of the vertical movement is shifted so that the cutting depths in the direction perpendicular to the rotation direction of the master 25 are not always the same in the plurality of cutting grooves produced by cutting. By repeating this process, a master plate 25 having a convex shape in which the height of the columnar convex portion is continuously changed is obtained. By staggering the timing of the vertical movement, the top of the columnar projection has a meandering and wavy shape when viewed from above. FIG. 5D is a perspective view of the master 25 in a flat plate shape.
Alternatively, while the roll-shaped master 25 is being rotated, a cutting tool 26 having a tip portion of a predetermined shape is applied to the master 25 so as to cut a predetermined depth, thereby cutting the master 25 in a spiral shape. By determining the number of rotations of the roll and the moving distance of the cutting tool, continuous machining is possible, and machining with improved machining efficiency is also possible. At this time, the cutting tool 26 is vertically moved 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 disk 25, thereby forming a cutting groove as shown in FIG. 5D. is obtained.
A mold (replica) having an inverted shape to which the convex shape of the master 25 is transferred is produced, and by pressing this mold against an uncured resin sheet, the convex shape of the master 25 is transferred to the resin sheet, By curing the resin sheet, the first optical layer 21 can be obtained.
By pressing the master 25 against an uncured resin sheet, or 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, A first optical layer 21 can also be obtained. However, in this case, in the top view of the first optical layer 21, the solid line and the broken line are interchanged in FIG. 5B. That is, when viewed from the top, the tops of the columnar protrusions are straight, and when viewed from the top, the bottoms of the valleys between the columnar protrusions are meandering and wavy.

Next, another aspect 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 projections 31A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 6B, thick wavy solid lines indicate the peaks of the columnar protrusions 31A, and broken lines indicate the valleys between the columnar protrusions.
As shown in FIGS. 6A and 6B , in the first optical layer 31 of one embodiment of the present invention, although the heights of the columnar protrusions 31A are the same, the tops of the columnar protrusions 31A It meanders in a direction orthogonal to the height direction. In addition, in the top view of FIG. 6B, both the crest and the bottom meander.
The first optical layer 31 in FIGS. 6A and 6B is produced, 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, roll-shaped. While rotating the master 35, a cutting tool 36 having a tip portion of a predetermined shape is brought into contact with the master 35 to cut the master 35. - 特許庁By moving the cutting tool 36 horizontally during cutting, a meandering cut groove can be obtained without changing the cutting depth. When the cutting of one round of the master disk 35 is completed, the cutting tool 36 is moved by a predetermined distance in the direction perpendicular to the rotation direction, and the cutting of the master disk 35 is resumed. At this time, the timing of the lateral movement is the same timing as before. That is, the timing of lateral movement is made the same so that a plurality of cutting grooves generated by cutting meander in the same shape from the start of cutting to the end of cutting. By repeating this process, a master plate 35 having a convex shape in which the apex of each columnar convex portion 31A meanders in a direction orthogonal to the extending direction and the height direction is obtained. In this master 35, the heights of the columnar protrusions 31A are the same. FIG. 6D is a perspective view of the master 35 in a flat plate shape.
The master 35 is pressed against an uncured resin sheet, or an uncured resin sheet is pressed against the master 35, the convex shape of the master 35 is transferred to the resin sheet, and the resin sheet is cured to obtain the first of the optical layer 31 can be obtained.
Alternatively, instead of the above-described transfer method, a mold (replica) having a reversed shape is produced by transferring the convex shape of the master 35, and the mold is pressed against an uncured resin sheet to transfer the master 35. By transferring the convex shape to the resin sheet and curing the resin sheet, the first optical layer 31 can be obtained.

Next, another aspect 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 projections 41A extending in one direction are arranged one-dimensionally in one direction.
In FIG. 7B, thick wavy solid lines indicate the peaks of the columnar protrusions 41A, and broken lines indicate the valleys between the columnar protrusions.
As shown in FIGS. 7A and 7B, in the first optical layer 41 of one embodiment of the present invention, although the heights of the columnar protrusions 41A are the same, the tops of the columnar protrusions 41A It meanders in a direction orthogonal to the height direction. In addition, in the top view of FIG. 7B, although the crest is meandering, the bottom of the valley is linear.
The first optical layer 41 in FIGS. 7A and 7B is produced, 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, roll-shaped. While the master 45 is being rotated, a cutting tool 46 having a tip portion of a predetermined shape is applied to the master 45 to cut the master 45 . During cutting, the cutting tool 46 is pendulum-moved with the tip as an axis, so that the cutting tip is linear and a meandering cutting groove can be obtained. When the cutting of one round of the master 45 is completed, the cutting tool 46 is moved by a predetermined distance in the direction perpendicular to the rotation direction, and the cutting of the master 45 is resumed. At this time, the timing of the pendulum motion is the same timing as before. That is, the timing of the pendulum motion is made the same so that the plurality of cut grooves generated by cutting meander in the same shape from the start of cutting to the end of cutting. By repeating this process, a master plate 45 having a convex shape in which the apex of each columnar convex portion 41A meanders in a direction orthogonal to the extending direction and the height direction is obtained. In this master 45, the heights of the columnar protrusions 41A are the same. FIG. 7D is a perspective view of the master 45 in a flat plate shape.
A mold (replica) having an inverted shape is produced by transferring the convex shape of the master 45, and by pressing this mold against an uncured resin sheet, the convex shape of the master 45 is transferred to the resin sheet, By curing the resin sheet, the first optical layer 41 can be obtained.

Next, another aspect 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, thick straight solid lines indicate the tops of the columnar protrusions 51A, and dashed lines indicate the valleys between the columnar protrusions.
As shown in FIGS. 8A and 8B, in the first optical layer 51 of one embodiment of the present invention, the heights of adjacent columnar convex portions 51A are different. Note that in the top view of FIG. 8B, both the top and the bottom are linear.
The first optical layer 51 in FIGS. 8 and 8B is produced, 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, roll-shaped. While rotating the master 55, a cutting tool 56 having a tip portion 56A of a predetermined shape is brought into contact with the master 55 to cut the master 55. As shown in FIG. After cutting one round of the master disk 55, the master disk 55 is cut by using a cutting tool 56 having a tip portion 56B having a tip shape different from that of the tip portion 56A from a position moved by a predetermined distance in the direction perpendicular to the rotation direction. resume cutting. By repeating this process, a master 55 having convex shapes in which adjacent columnar convex portions 51A have different heights is obtained. FIG. 8D is a perspective view of the master 55 in a flat plate shape.
The first optical layer 51 can be obtained by pressing the master 55 against an uncured resin sheet, transferring the convex shape of the master 55 to the resin sheet, and curing the resin sheet.

Next, another aspect 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 projections 61A extending in one direction are one-dimensionally arranged in one direction.
In FIG. 9B, the thick linear solid line indicates the top of the triangular prismatic protrusion, the thick linear dashed line indicates the top of the columnar protrusion having a curved surface, and the broken line indicates the valley between the columnar protrusions. .
As shown in FIGS. 9A and 9B, in the first optical layer 61 of one embodiment of the present invention, triangular prism-shaped convex portions and curved columnar convex portions are adjacent to each other.
The first optical layer 61 in FIGS. 9 and 9B is produced, 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, roll-shaped. While rotating the master 65, a cutting tool 66 having a predetermined triangular tip portion 66A is applied to the master 65 to cut the master 65. As shown in FIG. After cutting one round of the master disk 65, a cutting tool 66 having a tip portion 66B having a curved tip shape different from that of the tip portion 66A is used from a position moved by a predetermined distance in the direction perpendicular to the rotation direction. , the cutting of the master 65 is resumed. By repeating this process, a master plate 65 having a convex shape in which a triangular columnar 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 a flat plate shape.
A mold (replica) having a reversed shape to which the convex shape of the master 65 is transferred is prepared, and the mold is pressed against an uncured resin sheet to transfer the convex shape of the master 65 to the resin sheet, By curing the resin sheet, the first optical layer 61 can be obtained.

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

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. , 20 μm to 100 μm are particularly preferred.
Here, the height will be explained with reference to the drawings. 10A and 10B are schematic cross-sectional views of the first optical layer in a direction perpendicular to the direction in which the plurality of convex portions are arranged one-dimensionally.
The height (H) is, as shown in FIGS. 10A and 10B, the height of the convex portion in the cross section of the first optical layer 71 in the direction perpendicular to the direction in which the plurality of convex portions are arranged one-dimensionally. Refers to the height from the bottom to the top. Here, the bottom (B) of the projection corresponds to an imaginary line connecting two valleys sandwiching the projection. The height (H) is the distance from the top of the projection to the intersection of the perpendicular line from the top of the projection to the plane of the first optical layer 71 and the bottom (B) of the projection. .

In the first optical layer, the average value of the distance (pitch) between the plurality of convex portions is not particularly limited and can be appropriately selected depending on the purpose. ~900 µm is more preferred, 40 µm to 300 µm is even more preferred, and 45 µm to 90 µm is particularly preferred.
Here, the distance (pitch) will be described with reference to the drawings. 11A and 11B are schematic cross-sectional views of the first optical layer in a direction perpendicular to the direction in which the plurality of convex portions are arranged one-dimensionally.
The distance (pitch) (P) is, as shown in FIGS. Refers to the distance between the tops of matching protrusions. Here, when the heights of the tops of adjacent convex portions are different, the distance (pitch) (P) is the normal (L _l ) from the top of one convex portion to the plane of the first optical layer 71. , refers to the distance from the top of another convex portion adjacent to the one convex portion to the perpendicular line (L _r ) to the plane of the first optical layer 71 .

The height and the distance can be obtained, for example, by observing an electron micrograph of a cross-sectional view.
The average value can be obtained by arbitrarily measuring 50 points of the convex shape satisfying at least one of (1) to (4).

The shape of the convex portion is, for example, triangular in a cross section perpendicular to the extending 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 may be 25 μm to 35 μm.
When the convex shape satisfies the above (1), for example, the height change 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 is periodic, and the amplitude (A) in the change is 5 μm to 5 μm from the viewpoint of reducing local reflection of upward reflection. 65 μm is preferred. In addition to the reduction of local reflection of upward reflection, the amplitude (A) is more preferably 5 μm to 40 μm, particularly preferably 10 μm to 30 μm, considering the workability of mastering and the inflow of the resin component into the master. .
When the convex shape satisfies the above (1), the ratio between the amplitude (A) and the period (Pe) [amplitude (μm)/period (μm)] is preferably 0.6% to 7.8%, From the viewpoint of reduction of local reflection of upward reflection and workability, 0.6% to 5.0% is more preferable, and 1.2% to 3.8% is particularly preferable.
Regarding the amplitude change range, for example, a sine wave, a wavy curve with gradually increasing curvature such as a cycloid curve, an involute curve, a curve due to a combination of sine waves of higher harmonics, and a curve due to a combination thereof etc. can be applied, and the tilt angle (E), which is the maximum amount of change in that case, is preferably in the range of 1.1 deg to 13.7 deg. If the angle range is larger than the cutting angle when biting the cutting edge of the cutting blade into the cutting edge, the cutting blade may scratch the surface after processing. Therefore, from the standpoint of master disk 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.
Further, the deviation (ΔPh) of the periodic change in the height of the adjacent columnar protrusions is preferably 1/4 period to 3/4 period, more preferably 1/3 period to 2/3 period, and 2 /5 period to 3/5 period are even more preferred, and 1/2 period is particularly preferred.
Here, the average height (AH), the amplitude (A), the period (Pe), the tilt angle (E) that is the maximum amount of change, and the deviation of the periodic change (ΔPh) will be described with reference to the drawings.
FIG. 18A shows a diagram for explaining the average height (AH), the amplitude (A), the period (Pe), and the tilt angle (E) that becomes the maximum amount of change. This figure is a cross-sectional view of the columnar projection as viewed from the extending direction and the direction perpendicular to the thickness direction.
The average height (AH) is the average value from the bottom of the protrusion to the height of the protrusion.
Amplitude (A) is the difference between the highest and lowest height changes.
The period (Pe) is the period of the varying height.
The tilt angle (E), which is the maximum amount of change, is the differential value of the change in height at the position where the change in height is maximum.
FIG. 18B shows a diagram for explaining the deviation (ΔPh) of periodic change.
In FIG. 18B, the solid-line curve is the ridgeline of the first columnar protrusion, and the broken-line curve is the ridgeline of the second columnar protrusion adjacent to the first columnar protrusion.
The shift in periodic change (ΔPh) is the shift in periodic change in the height of two adjacent columnar protrusions. In FIG. 18B, the periodic variation offset (ΔPh) is 1/2 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 may be 25 μm to 35 μm.
When the convex shape satisfies the above (2), for example, the meandering is periodic, and the meandering period (Peb) may be, for example, 400 μm to 1,200 μm, or 600 μm to 1,000 μm. or 700 μm to 900 μm.
When the convex shape satisfies the above (2), for example, meandering is periodic, and the meandering amplitude (Ab) is preferably 5 μm to 65 μm from the viewpoint of reducing local reflection of upward reflection. In addition to the reduction of local reflection of upward reflection, the amplitude (Ab) is more preferably 5 μm to 40 μm, particularly preferably 10 μm to 30 μm, considering the workability of mastering and the inflow of the resin component into the master. .
When the convex shape satisfies the above (2), the ratio (amplitude/period) between the amplitude (Ab) and the period (Peb) is preferably 0.6% to 7.8%. From the viewpoint of reduction and workability, 0.6% to 5.0% is more preferable, and 1.2% to 3.8% is particularly preferable.
The meandering change range is, for example, a sine wave, a cycloid curve, a wavy curve with gradually increasing curvature such as an involute curve, a curve resulting from a combination of sine waves of higher harmonics, and a curve resulting from a combination thereof. etc. can be applied, and the tilt angle (Eb), which is the maximum amount of change in that case, is preferably in the range of 1.1 deg to 13.7 deg. If the angle range is larger than the cutting angle when biting into the cutting edge of the cutting blade, the cutting blade will damage the surface after processing, which is not preferable. Therefore, from the standpoint of master disk processing, 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.
Further, the deviation (ΔPhb) of the meandering periodic change of adjacent columnar protrusions is preferably 1/4 period to 3/4 period, more preferably 1/3 period to 2/3 period, and 2/ 5 to 3/5 periods are even more preferred, and 1/2 period is particularly preferred.
Here, the amplitude (Ab), the period (Peb), the tilt angle (Eb) that is the maximum amount of change, and the deviation of the periodic change (ΔPhb) will be described with reference to the drawings.
FIG. 19 shows a diagram for explaining the amplitude (Ab), the period (Peb), the tilt angle (Eb) that is the maximum change amount, and the deviation of the periodic change (ΔPhb). This figure is a top view of the columnar protrusion as viewed from above.
In FIG. 19, the solid curved line is the ridge line of the columnar protrusion, and the dashed line indicates the valley between the two protrusions.
Amplitude (Ab) is the width of the meander.
Period (Peb) is the period in the periodic meander.
The tilt angle (Eb), which is the maximum amount of change, is the differential value of the meandering change at the position where the meandering change is maximum.
In FIG. 19, the deviation of periodic change (ΔPhb) is 1/2 period.

<When the convex shape satisfies the above (3)>
When the convex shape satisfies the above (3), the absolute value of the height difference 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.

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 curved columnar protrusions in (4) above , preferably periodic. The reason is as follows.
It is also possible to randomly arrange the changes in the structures (convex portions). However, as a result of random arrangement, if a structure with a large height size and a structure with a small height size are lined up in succession, once a structure with a height Before the light reflected by the high structure hits the structure that is reflected again by the tall structure, it passes through the resin of the transparent body for a long distance, and the absorption rate may increase. May reduce efficiency. In particular, when the purpose is to retroreflect heat rays on a window glass, an increase in the absorptivity causes a local rise in temperature, causing a "thermal cracking" phenomenon that originates from defects inherent in the glass itself. there is a risk of In order to reduce the risk of "thermal cracking", it is desirable to reflect light in the shortest path, and it is desirable to reduce unevenness in the height of the reflecting structure. From this point of view, it is also possible to alleviate such problems by, for example, causing a change in the reflection structure with periodicity.

As for the inclination of the convex slope, it is preferable to provide an angle of 45° or more. This is for the purpose of not impairing the efficiency of solar reflection, and if the inclination is gentle, primary reflection occurs like the reflectivity on a flat surface, making it difficult to obtain retroreflection through multiple reflections.

In the optical body, the entire one surface of the first optical layer may have the predetermined convex shape, or a part of the one surface of the first optical layer may have the predetermined convex shape. may have. When a part of one surface of the first optical layer has the above-described predetermined convex shape, it is preferable to have the above-described predetermined convex shape at a portion where local strong reflection in specular reflection is desired to be reduced.

As one aspect of the optical body of the present invention, the aspect in which only convex shapes arranged one-dimensionally are present on one surface of the first optical layer has been mentioned, but as another aspect of the optical body of the present invention, Alternatively, one surface of the first optical layer may be composed of a two-dimensional array in which two of the one-dimensional arrays are combined.
The two-dimensional array is formed by combining two one-dimensional arrays. The two-dimensional array is a two-dimensional array in which one one-dimensionally arranged convex shape and another one-dimensionally arranged convex shape having a different extension direction and angle are combined. In this case, one or both of the one-dimensionally arranged convex shapes satisfy at least one of the following (1) to (4).
(1) In each columnar protrusion, the height changes in the extending direction.
(2) In each columnar protrusion, the apex meanders in a direction perpendicular to both the extending direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped convex portion is adjacent to a columnar convex portion having a curved surface.

In the corner cube body, retroreflection is achieved by reflecting three times on the reflecting surface. In the case of an optical layer having an array of convex shapes, the number of times of reflection is reduced and solar radiation absorption can be suppressed.
In addition, in the corner cube body, retroreflection is achieved by reflecting three times on the reflecting surface, but in the corner cube body, part of the light is reflected twice and leaks in directions other than the retroreflection. In the case of a one-dimensional arrangement only, or in the case of the two-dimensional arrangement, it is possible to have a shape that reflects more to the sky side.

From the viewpoint of imparting design to optical members, window materials, etc., the first optical layer has the property of absorbing light of a specific wavelength in the visible region within a range that does not impede transparency to visible light. may
Designability, that is, the characteristic of absorbing light of a specific wavelength in the visible region can be achieved 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 according to the purpose. Examples thereof include inorganic pigments and organic pigments. It is preferable to use a system pigment.
_The inorganic pigment is not particularly limited and can be appropriately selected _depending on the intended purpose. , Sb-doped _TiO2 or Cr, W-doped _TiO2 ), chrome green ( _{Cr2O3 ,} etc.), peacock ( _{(CoZn)O(AlCr)2O3 ) ,} Victoria green ((Al,Cr) _2O3 ) , Prussian Blue ( _{CoO.Al2O3.SiO2 )} , Vanadium Zirconium Blue (V-doped _{ZrSiO4 )} , Chrome Tin Pink (Cr _- doped _{CaO.SnO2.SiO2 )} , Ceramic Red (Mn-doped _Al2O3 ), salmon pink (Fe-doped ZrSiO ₄ ) and the like.
The organic pigment is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include azo pigments and phthalocyanine pigments.

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

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

As the (meth)acrylate, it is preferable to use a monomer and/or oligomer having two or more (meth)acryloyl groups. Examples of the monomer and/or oligomer include urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, polyol (meth)acrylate, polyether (meth)acrylate, and melamine (meth)acrylate. be able to. Here, the (meth)acryloyl group means either an acryloyl group or a methacryloyl group. Here, an oligomer means a molecule having a molecular weight of 500 or more and 60000 or less.

Examples of polyfunctional monomers that can be used in the UV-curable resin composition include ethanediol diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate, and 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, 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 diacrylate of hydroxypivalic acid ester neopentyl glycol ester, ethylene oxide-modified isocyanuric acid diacrylate, pentaerythritol diacrylate monostearate, 1,6-hexanediol diglycidyl Ether acrylic acid adduct, polyoxyethylene epichlorohydrin-modified bisphenol A diacrylate, tricyclodecanedimethanol diacrylate, tricyclodecanedimethanol dimethacrylate, trimethylolpropane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, poly Ethylene 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-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 hexa Acrylate, polycaprolactone-modified dipentaerythritol hexaacrylate, dioxane glycol diacrylate, caprolactone-modified tris(acryloxyethyl) isocyanurate and the like.

As the photopolymerization initiator, one appropriately selected from known materials can be used. As known materials, for example, benzophenone derivatives, acetophenone derivatives, anthraquinone derivatives, and the like can be used alone or in combination. The blending amount of the polymerization initiator is preferably 0.1% by mass or more and 10% by mass or less based on the solid content. If it is less than 0.1% by mass, the photocurability may be lowered, and it may be substantially unsuitable for industrial production. On the other hand, if it exceeds 10% by mass, the odor tends to remain in the coating film 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, (meth)acrylate, a photopolymerization initiator, and the like are referred to as solid content.

<Inorganic layer>
The inorganic layer is a layer arranged 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. Details of an example of the reflective layer will be described later.

The average film thickness of the inorganic layer is not particularly limited and can be appropriately selected depending on the intended purpose. When the average film thickness is 20 μm or less, the optical path through which the transmitted light is refracted becomes short, 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 intended purpose.

The type of the inorganic layer is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include laminated films, transparent conductive layers, functional layers, and semitransparent layers. These may be used alone or in combination of two or more.

The inorganic layer is, for example, semi-permeable.
Here, the semi-transmissivity means that the transmittance at a wavelength of 500 nm or more and 1,000 nm or less is 5% or more and 70% or less, preferably 10% or more and 60% or less, more preferably 15% or more and 55% or less. . The semi-transmissive layer is a reflective layer having a transmittance of 5% to 70%, preferably 10% to 60%, more preferably 15% to 55% at a wavelength of 500 nm to 1,000 nm. .

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

-metal layer-
A metal having a high reflectance in the infrared region is used for the metal layer.
Metals having high reflectance in the infrared region are not particularly limited and can be appropriately selected depending on the purpose. Examples include Au, Ag, Cu, Al, Ni, Cr, Ti, Pd, Co, Si, Simple substances such as Ta, W, Mo, and Ge, and alloys containing two or more of these simple substances are included. Among these, Ag-based, Cu-based, Al-based, Si-based, and Ge-based materials are preferable in terms of practicality.
The alloy is not particularly limited and can be appropriately selected depending on the intended purpose. etc. are preferable.
In order to suppress corrosion of the metal layer, it is preferable to add materials such as Ti and Nd to the metal layer. In particular, when Ag is used as the material of the metal layer, it is preferable to add the above materials.

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

For the purpose of preventing oxidative deterioration of the lower layer metal during film formation of the optical transparent layer, a thin buffer layer of Ti or the like having a thickness of several nanometers may be provided at the interface of the optical transparent layer to be formed. Here, the buffer layer is a layer for suppressing oxidation of the lower layer such as the metal layer by oxidizing itself when the upper layer is formed.

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

<<Function layer>>
The functional layer is a layer containing, as a main component, a chromic material that reversibly changes its reflection performance or the like by an external stimulus.
The chromic material is a material that reversibly changes its structure by external stimuli such as heat, light, and intruding molecules.
The chromic material is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include photochromic materials, thermochromic materials, gaschromic materials, electrochromic materials, and the like.

The photochromic material is a material that reversibly changes its structure by 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 rays.
_{The photochromic} material is not particularly limited and _can be appropriately selected depending on the _intended purpose _. oxides, and the like. Also, by stacking a layer having a different refractive index from these layers, the wavelength selectivity can be improved.

The thermochromic material is a material that reversibly changes its structure by the action of heat.
The thermochromic material can reversibly change various physical properties such as reflectance and color by heating.
The thermochromic material is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include VO ₂ and the like. Elements such as W, Mo and F can also be added for the purpose of controlling the transition temperature and transition curve.
Alternatively, a laminated structure may be employed in which a thin film containing a thermochromic material such as _VO2 as a main component is sandwiched between antireflection layers containing a high refractive index material such as _TiO2 or ITO as a main component.

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

Electrochromic materials are materials that can reversibly change various physical properties such as reflectance and color by electricity.
As the electrochromic material, for example, a material that reversibly changes its structure by voltage application can be used. Specific examples of the electrochromic material are not particularly limited and can be appropriately selected depending on the intended purpose. be done.
Specifically, the reflective light-modulating material is a material whose optical properties can be controlled between a transparent state, a mirror state, and/or an intermediate state thereof by an external stimulus. The reflective light-modulating material is not particularly limited and can be appropriately selected according to _the purpose. and materials in which needle-like crystals having selective reflectivity are confined in microcapsules.

The specific structure of the functional layer is not particularly limited and can be appropriately selected depending on the intended purpose. A structure in which a thin buffer layer such as Al, an electrolyte layer such as Ta ₂ O ₅ , an ion storage layer such as WO ₃ containing protons, and a transparent conductive layer are laminated, (ii) a transparent conductive layer on the second optical layer, Examples include a structure in which an electrolyte layer, an electrochromic layer such as _WO3 , and a transparent conductive layer are laminated.
In these configurations, protons contained in the electrolyte layer are doped or dedoped into the alloy layer by applying a voltage between the transparent conductive layer and the counter electrode. This changes the transmittance of the alloy layer. It is also desirable to laminate the electrochromic material with a high refractive index material such as _TiO2 or ITO to enhance wavelength selectivity.
Further, as another configuration, a configuration in which a transparent conductive layer, an optical transparent layer in which microcapsules are dispersed, and a transparent electrode are laminated on the second optical layer can be mentioned. In this structure, by applying a voltage between the two transparent electrodes, the needle-shaped crystals in the microcapsules are oriented in a transmissive state. can do.

<<Semi-transmissive layer>>
The semi-transmissive layer is composed of, for example, a single layer or multiple layers of metal layers and has semi-transmissive properties.
The material of the metal layer is not particularly limited and can be appropriately selected according to the purpose.

<Second optical layer>
The second optical layer is a layer arranged on the inorganic layer side so that the convex shape is buried.
The second optical layer protects the inorganic layer, for example.
Examples of the material of 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 a smooth surface and the other surface is concave. The convex shape of the first optical layer and the concave shape of the second optical layer have a relationship in which the concaves and convexes are reversed to each other.

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

The optical body has transparency. As for transparency, it is preferable to have a range of transmission 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 appear blurred. When the refractive index difference is in the range of more than 0.008 to 0.010 or less, there is no problem in daily life although it depends on the brightness of the outside. When the refractive index difference is in the range of more than 0.005 to 0.008 or less, the outside scenery can be seen clearly, although the diffraction pattern is disturbed only by a very bright object such as a light source. If the refractive index difference is 0.005 or less, the diffraction pattern is almost unnoticeable. Of the first optical layer and the second optical layer, the optical layer to be attached to a window material or the like may contain an adhesive as a main component. With such a configuration, the optical body can be attached to a window material or the like by the first optical layer or the second optical layer containing an adhesive material as a main component. In addition, when using such a structure, it is preferable that the refractive index difference of an adhesive is in the said range.

The first optical layer and the second optical layer preferably have the same optical characteristics 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 having transparency in the visible region. When the first optical layer and the second optical layer are made of the same material, the refractive indices of both become equal, so that the transparency of visible light can be improved. However, even if the same material is used as a starting material, it is necessary to pay attention to the fact that the refractive index of the finally formed layer may differ depending on the curing conditions in the film formation process. On the other hand, if the first optical layer and the second optical layer are made of different materials, the refractive indexes of the layers are different. It tends to refract and blur the transmitted image. In particular, there is a tendency for the diffraction pattern to be conspicuously observed when observing an object that is close to a point light source, such as a distant lamp. An additive may be mixed in the first optical layer and/or the second optical layer in order to adjust the refractive index value.

The first optical layer and the second optical layer preferably have transparency in the visible region. Here, the definition of transparency has two meanings: no absorption of light and no scattering of light. In general, the term "transparency" sometimes refers only to the former, but the optical body preferably has both. The retroreflectors currently in use are intended to make the reflected light visible from road signs and the clothing of workers at night. If so, the reflected light can be seen. For example, even if the front surface of the image display device is subjected to an anti-glare treatment having a scattering property for the purpose of imparting anti-glare properties, the image can still be viewed based on the same principle. However, one embodiment of the optical body is characterized in that it transmits directionally reflected light other than a specific wavelength. For viewing purposes, no light scattering is preferred. However, depending on the application, it is also possible to intentionally impart scattering properties to the second optical layer.

The optical body is preferably used by attaching it to a rigid body (for example, a window material) that is mainly transparent to the transmitted light other than the specific wavelength through 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 an architectural window material, it is particularly preferable to apply the optical film to a window material arranged in any direction between east, south and west (for example, southeast and southwest). This is because heat rays can be reflected more effectively by applying to the window material at such a position. The optical body can be used not only for single-layer window glass, but also for special glass such as multi-layer glass. Moreover, the window material is not limited to glass, and may be made of a transparent polymeric material. The optical layer preferably has transparency in the visible region. This is because, when the optical body is adhered to a window material such as a window glass, visible light can be transmitted through the optical body by having the transparency in this way, and sunlight can be admitted. Moreover, as the surface to be bonded, not only the inner surface of the glass but also the outer surface can be used.

Further, the optical body can be used in combination with other heat ray blocking films, and for example, a light absorbing coating film can be provided on the interface between the air and the optical body (that is, the outermost surface of the optical body). The optical body can also be used in combination with a hard coat layer, an ultraviolet cut layer, a surface antireflection layer, and the like. When these functional layers are used together, it is preferable to provide these functional layers at the interface between the optical body and air. However, since it is necessary to place the UV cut layer closer to the sun than the optical body, especially when it is used for lining on the window glass surface of the room, it is necessary to place it between the window glass surface and the optical body. It is desirable to provide an ultraviolet cut layer. In this case, an ultraviolet absorber may be kneaded into the bonding layer between the window glass surface and the body.

Also, depending on the use of the optical body, the optical body may be colored to impart a design property. When imparting a design in this way, it is preferable that the optical layer absorb only light in a specific wavelength band within a range that does not impair the transparency.

An example of the optical body of the present invention will now 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 invention. The optical body of FIG. 12 has the first optical layers 11 shown in FIGS. 4A and 4B.
In FIG. 12, the optical body 10 includes a first optical layer 11 having a convex surface, an inorganic layer 12 disposed on the surface of the first optical layer 11 on the side having the convex shape, On the inorganic layer 12 side, the second optical layer 13 is arranged so that the convex shape is buried, and the first optical layer 13 is arranged on the surface of the first optical layer 11 facing the surface having the convex shape. and a substrate 14 .

<Wavelength selective reflectivity>
13A and 13B are cross-sectional views for explaining an example of the function of the optical body. Here, as an example, a case where the convex portion has a prism shape with an inclination angle of 45° will be described.
As shown in FIG. 13A, part of the light _L1 reflected upward from the sunlight incident on the optical body 10 is directionally reflected in the same direction as the incident direction, whereas the light L1 Light L ₂ that is not reflected is transmitted through the optical body 10 .
Further, as shown in FIG. 13A, the light incident on the optical body 10 and reflected by the reflecting film surface of the inorganic layer 12 (wavelength selective reflecting layer) is reflected upward at a rate corresponding to the incident angle. ₁ and light L ₂ that is not reflected in the sky. The light _L2 that is not reflected upward is totally reflected at the interface between the second optical layer 13 and the air, and then finally reflected in a direction different from the incident direction.
Let α be the incident angle of light, n be the refractive index of the second optical layer 13, and _R be the reflectance of the wavelength selective reflection layer. 1).
x=(sin(45-α')+cos(45-α')/tan(45+α'))/(sin(45-α')+cos(45-α'))×R ² (1)
However, α'=sin ⁻¹ (sinα/n)
When the proportion of the light _L1 that is not reflected to the sky increases, the proportion of the incident light that is reflected to the sky decreases. In order to improve the rate of reflection to the sky, it is effective to devise the shape of the wavelength selective reflection layer, that is, the convex shape of the first optical layer 11 .

FIG. 14 is a perspective view showing the relationship between incident light incident on the optical body 10 having wavelength-selective reflectivity and 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 directionally reflects the light _L1 in a specific wavelength band out of the light L incident on the incident surface S1 at the incident angle (θ, φ) in a direction other than specular reflection (−θ, φ+180°). On the other hand, it transmits light _L2 other than the specific wavelength band. In addition, the optical body 10 has transparency to light other than the specific wavelength band. As for transparency, it is preferable to have a range of transmission image clarity described later. where θ is the angle between the normal _l1 to the plane of incidence S1 and the incident light L or the reflected light _L1 (hereinafter, "θ" may be referred to as the vertical angle). φ: An angle between a specific straight line _l2 in the plane of incidence S1 and a component of the incident light L or reflected light _L1 projected onto the plane of incidence S1 (hereinafter, “φ” may be referred to as an azimuth angle ). Here _, the specific straight line _l2 in the plane of incidence is defined as φ This is the axis in which the intensity of reflection in the direction is maximized. However, if there are multiple axes (directions) with the maximum reflection intensity, one of them is selected as the straight line _l2 . The clockwise rotation angle θ with respect to the perpendicular _l1 is defined as "+θ", and the counterclockwise rotation angle θ is defined as "-θ". The angle φ rotated clockwise with respect to the straight line _l2 is assumed to be "+φ", and the angle φ rotated counterclockwise is assumed to be "-φ".

The specific wavelength band of light that is selectively directionally reflected and the specific light that is transmitted differ 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, light in a specific wavelength band that is selectively directionally reflected is near-infrared light, and light in a specific wavelength band that is transmitted is visible light. Light is preferred. Specifically, it is preferable that the light in the specific wavelength band that is selectively directionally reflected is mainly near-infrared rays in the wavelength band of 780 nm or more and 2100 nm or less. By reflecting near-infrared rays, temperature rise in a building can be suppressed when the optical body is attached to a window material such as a glass window. Therefore, it is possible to reduce the cooling load and save energy. Here, directional reflection means that the intensity of reflected light in a specific direction other than regular reflection is stronger than the intensity of regular reflected light and sufficiently stronger than the intensity of non-directional diffuse reflection. Here, "reflect" means that the reflectance in a specific wavelength band, for example, the near-infrared region, is preferably 30% or more, more preferably 50% or more, and still more preferably 80% or more. Transmitting means that the transmittance in a specific wavelength band, for example, the visible light region is preferably 30% or more, more preferably 50% or more, and still more preferably 70% or more.

In the optical body 10 having wavelength-selective reflectivity, the directional reflection direction φo is preferably −90° or more and 90° or less. 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. The optical body 10 within this range is useful when there are no tall buildings in the vicinity. Moreover, it is preferable that the direction of directional reflection is in the vicinity of (θ, -φ). The vicinity means a deviation within a range of preferably 5 degrees or less, more preferably 3 degrees or less, and still more preferably 2 degrees or less from (θ, -φ). With this range, when the optical body 10 is attached to the external support, light in a specific wavelength band among the light incident from the sky above the buildings lined up with similar heights can be efficiently transferred to the sky above the other buildings. because it can be returned. In order to achieve such directional reflection, it is preferable to use a three-dimensional structure such as a portion of a sphere or hyperboloid, a triangular pyramid, a square pyramid, or a cone. Light incident from the (θ, φ) direction (−90°<φ<90°) is converted to (θo, φo) direction (0°<θo<90°, −90°<φo<90° ) can be reflected. Alternatively, it is preferable to form a columnar body extending in one direction. Light incident from the (θ, φ) direction (−90°<φ<90°) is reflected in the (θo, −φ) direction (0°<θo<90°) based on the tilt angle of the columnar body. can be done. Therefore, when the heights of buildings are about the same, it is applicable to reflect the (φ, θ) incidence in the (φ0, −θ) direction. In the present invention, if the height of the building is higher than that of the building where the sun shines, or if the building is nearby and the reflected light shines, the local reflection of the sun can be mitigated by combining the elements of the present invention. It becomes possible.

In the optical body 10 having wavelength-selective reflectivity, directional reflection of light in a specific wavelength band is reflected in a direction near the retroreflection, i. is preferably near (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 still more preferably within 2 degrees. This is because when the optical body 10 is attached to an external support, the light in the specific wavelength band among the light incident from the sky can be efficiently returned to the sky by setting the thickness in this range. Therefore, if the heights of buildings are about the same, the (φ, θ) incidence can be efficiently reflected upward by changing it to (φ0, −θ). In the present invention, if the height of the building is higher than that of the building where the sun shines, or if the building is nearby and the reflected light shines, the local reflection of the sun can be mitigated by combining the elements of the present invention. It becomes possible. In addition, when the infrared light emitting part and the light receiving part are adjacent to each other, such as an infrared sensor or infrared imaging, the retroreflection direction must be the same as the incident direction, but there is no need to perform sensing from a specific direction. need not be exactly in the same direction.

<Clearness of transmitted image>
In the optical body, regarding the transmission image definition in the wavelength band having transparency, the value when using an optical comb of 2.0 mm is not particularly limited, and can be appropriately selected according to the purpose. 60% or more is preferable, and 75% or more is more preferable.
Furthermore, in the optical body, regarding the transmission image clarity in the wavelength band having transparency, the value when using an optical comb of 0.5 mm is not particularly limited, and can be appropriately selected according to the purpose. However, 60% or more is preferable, and 75% or more is more preferable. When the transmitted image definition value is 60% or more and less than 75%, the outside scenery can be seen clearly, although the diffraction pattern is disturbed only by a very bright object such as a light source. If the transmitted image definition value is 75% or higher, the diffraction pattern is of little concern.
Here, the transmission image definition value is measured according to JIS K-7374:2007 using ICM-1T manufactured by Suga Test Instruments. However, if the wavelength to be transmitted is different from the D65 light source wavelength, it is preferable to calibrate using a filter for the wavelength to be transmitted before measuring.

<Method for manufacturing optical body>
15A to 15, 16A to 16C, and 17A to 17D, an example of a method for manufacturing an optical body according to an embodiment of the present invention will be described below. Note that part or all of the manufacturing process described below is preferably performed by roll-to-roll in consideration of productivity. However, the manufacturing process of the mold shall be excluded.

The production example here is the production example of the optical body having the first optical layer 11 shown in FIGS. 4A and 4B.
First, as shown in FIG. 15A, a mold (replica) having a master plate 15 having the same convex shape as the convex shape of the first optical layer 11 or a reverse shape of the master plate 15 is formed by, for example, cutting tool processing or laser processing. to form The method of manufacturing the master 15 is as described with reference to FIGS. 4C and 4D. Next, as shown in FIG. 15B, the convex shape of the master 15 is transferred to a film-like resin material using, for example, a melt extrusion method or a transfer method. The transfer method includes pouring a photocurable resin composition into a mold and curing it by irradiating it with energy rays, applying heat and pressure to the resin to transfer the shape, or supplying a resin film from a roll and heating it. and a method of transferring the shape of the mold while adding (laminate transfer method). Thereby, as shown in FIG. 15C, the first optical layer 11 having a convex shape on one main surface is formed.

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

Next, as shown in FIG. 16A, a wavelength selective reflection layer (functional layer) is formed as the inorganic layer 12 on one main surface of the first optical layer 11 . The method for forming the wavelength-selective reflective layer as the inorganic layer 12 is not particularly limited and can be appropriately selected according to the purpose. method, die coating method, wet coating method, spray coating method, etc., and it is preferable to appropriately select from these film forming methods according to the shape of the convex shape. Next, as shown in FIG. 16B, annealing treatment 150 is applied to the wavelength selective reflection layer as the inorganic layer 12, if necessary. The temperature of the annealing treatment is, for example, within the range of 100° C. or higher and 250° C. or lower.

Next, as shown in FIG. 16C, the photocurable resin composition 13A is applied onto the wavelength selective reflection layer as the inorganic layer 12. Next, as shown in FIG.
Next, as shown in FIG. 17A, a laminate is formed by spreading the photocurable resin composition 13A to a predetermined thickness with a coater or the like to fill the convex shape.
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 ray is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include electron beams, ultraviolet rays, visible rays, gamma rays and electron beams. Among these, ultraviolet rays are preferable from the viewpoint of production facilities. The integrated irradiation amount is not particularly limited, and can be appropriately selected in consideration of the curing characteristics of the resin, suppression of yellowing of the resin and the first base material 14, and the like. The pressure to be 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 arise with the running properties of the film.
As a result, as shown in FIG. 17C, the second optical layer 13 is formed on the wavelength selective reflection layer 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 arranged 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 is due to the flatness of the coater head or the like and the thickness of the resin (how the unevenness is filled).

EXAMPLES 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 the upward reflection directivity was confirmed by simulation when the convex shape of the optical body was changed.

In Example 1, an optical body [an optical body satisfying the above (1)] in which the triangular cross-sectional height of the convex shape continuously changes in the extending direction 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 ・Period of sine wave (Pe): 800 μm
・Maximum tilt angle of top in extension direction (E): 1.1deg
・Difference (phase) with adjacent structures (ΔPh): 1/2 period

In order to confirm the effect of reflection due to the shape of the reflecting surface, a ray-tracing simulation was performed.
As quasi-parallel light, a sufficient number of light rays were emitted from the light source to the reflecting surface by the Monte Carlo method (the structure of the reflector is similar to that of the real object, and the reflecting surface is embedded in resin).
In the simulation, the near-infrared upward reflectance was calculated at a vertical angle (θ) from 20 degrees from the normal direction to the surface of the measurement sample. The azimuth angle (φ) of the incident sample was set to φ=0 deg.
For the evaluation of the reflected light, the intensity of the light beam was calculated for each 1 deg of the vertical direction angle and the azimuth angle in the same manner as the Mini Diff used for the actual measurement described later, and the following comparisons were made.

<Upward reflection>
From the distribution of the reflection intensity obtained by the simulation by the ray tracing method, the upward reflection component reflected to the sky side from the horizontal line including the normal to the light incident direction surface of the test model was counted, and the triangular prism of Comparative Example 1 described later was counted. The relative value % was calculated as the relative value of the upward reflection when the result of the numerical value of the upward reflection component in 100%.
Based on the relative value of this upward reflection, the degree of not impairing the upward reflection performance was evaluated.

<Local reflection>
From the distribution of reflection intensity obtained by simulation by the ray tracing method, the highest intensity value (peak reflection intensity) excluding specular reflection was read, and the highest intensity excluding specular reflection of the triangular prism of Comparative Example 1 described later. The relative value % when the result of the numerical value (peak reflection intensity) was taken as 100% was calculated as the local reflection intensity ratio.
The effect of suppressing local reflection was evaluated based on the relative value of the highest intensity value 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 reflex was evaluated according to the following criteria.
〔Evaluation criteria〕
・×: Light that is obliquely incident on the surface of the optical body is reflected in a straight line from the reflecting part, and has a local bright spot ・○: Light that is obliquely incident on the surface of the optical body is reflected Light is reflected non-linearly from the part, and the bright spots are band-shaped or divided into multiple parts to alleviate local bright spots.

(Examples 2 to 13, Comparative Examples 1 and 2)
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. In addition, 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 were summarized in graphs and shown in FIGS. 20 to 25. FIG.
FIG. 20 is a graph showing the relationship between the amplitude and the relative value of reflected light intensity (local reflected intensity ratio).
FIG. 21 is a graph showing the relationship between the amplitude/period and the relative value of reflected light intensity (local reflected intensity ratio).
FIG. 22 is a graph showing the relationship between the maximum change angle and the relative value of reflected light intensity (local reflected 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 reflected 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, compared to the triangular prism of Comparative Example 1, there is an amplitude change in height [corresponding to the aspect (1)], in-plane meandering [corresponding to the aspect (2)], and a triangular prism It was confirmed that the combination of the curved surface and the curved surface [corresponding to the aspect (4)] has a high effect of suppressing the local reflection.
In particular, compared with the in-plane meandering [corresponding to the aspect (2) above] and the combination of a triangular prism and a curved surface [corresponding to the aspect (4) above], there is an amplitude change in the height [corresponding to the aspect (1) above]. It has been confirmed that the effect of suppressing local reflection is higher in the case of [corresponding to the embodiment].
From FIGS. 23 to 25, it was confirmed that Comparative Example 2, which uses only the curved surface shape, has low upward reflection, and that the combination of the triangular prism of Example 13 and the curved surface shape can suppress local reflection while maintaining upward reflection. . This is probably because the curved surface shape of Comparative Example 2 does not cause multiple reflections necessary for upward direction.

(Example 14-1)
<Preparation of optical body>
In order to create structures with different heights continuously in the direction in which the triangular cross section shown in FIG. I made it so that the height is different. The optical body to be produced is an optical body that satisfies the above (1).

・Master disk processing specifications Average shape interval (distance between valleys of adjacent structures): 67 μm
Average shape height (AH): 31 μm
Section base angle - D1: 35deg
Section base angle -D2: 55deg
Height amplitude in extension direction (A): 10.5 μm
Height modulation in extension direction: sine wave Cycle of sine wave (Pe): 800 μm
Deviation (phase) with adjacent structures (ΔPh): 1/2 period Processing to give the height modulation a phase of 1/2 cycle)

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

An inorganic layer having the following structure for reflecting near-infrared rays was formed on the formed first optical layer by a vacuum sputtering method. A photocurable resin composition (resin refractive index after curing: 1.52) is applied onto the formed inorganic layer, and a PET substrate (manufactured by Toray Industries, Inc., thickness: 75 μm) is irradiated with ultraviolet rays to cure. A second optical layer was formed. As described above, 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. The results are shown in Table 2-2.

<<Structure of Inorganic Layer>>
(First optical layer)/Nb ₂ O ₅ (36 nm)/AgPdCu (11 nm)/Al ₂ O ₃ —ZnO (4 nm)/Nb ₂ O ₅ (80 nm)/AgPdCu (11 nm)/Al ₂ O ₃ —ZnO (4 nm)/Nb ₂ O ₅ (36 nm)/Al ₂ O ₃ —ZnO (4 nm)/(second optical layer)
Here, an alloy target containing a composition of Ag/Pd/Cu=98.1 mass %/0.9 mass %/1.0 mass % was used for the deposition of AgPdCu.
In addition, for the Al ₂ O ₃ —ZnO film formation, a ceramic target [ZnO:Al ₂ O ₃ =100:2 (mass ratio)] in which 2% by mass of Al ₂ O ₃ was added to ZnO was used _. Nb ₂ O ₅ was used for the deposition of O ₅ . Here, the thickness of each layer represents the thickness when a film is formed on a shapeless flat surface.

<Visible light transmittance, visible light reflectance, shielding coefficient>
A test was conducted according to 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 measured with a spectrophotometer (UH4150) manufactured by Hitachi High-Tech Science Co., Ltd.
Visible light transmittance, visible light reflectance and shielding coefficient were calculated according to JIS A5759 for the obtained spectral transmittance and reflectance values.
FIG. 26 shows a state in which the optical body is attached to the float glass using an adhesive. In FIG. 26, reference numeral 110 represents the second base material, reference numeral 111 represents float glass, and reference numeral 112 represents the adhesive. The symbol D1 represents the cross-sectional base angle -D1, and the symbol D2 represents the cross-sectional base angle -D2.

<Haze value>
A test was conducted according to JIS K7136 using the above sample. Specifically, the optical body was attached to a float glass having a thickness of 3 mm using a commercially available transparent adhesive material, and the haze meter (NDH7000) manufactured by Nippon Denshoku Industries Co., Ltd. was used for measurement.

<Near-infrared upward reflectance>
Using the sample used for optical measurement, 4.4 Directional reflection performance (http://www.env.go.jp/policy/ etv/pdf/list/h27/051-1506a.pdf), the near-infrared upward reflectance was measured at a vertical angle (θ) of 60 degrees from the normal to the surface of the measurement sample. The azimuth angle (φ) of the incident light with respect to the sample was set to the direction in which the upward reflection performance of the sample was most efficiently exhibited (for the vertical azimuth angle (θ), see FIG. 26, for example).
The obtained spectral reflectance value was multiplied by a weighting factor according to JIS A5759, and the upper reflection component in the near-infrared (780 to 2500 nm) region was calculated as the upper reflectance.

<Upward reflection directivity>
Reflection directivity was measured by Light Tec's MiniDiff to evaluate the effect of suppressing local reflection.
Light Tec's MiniDiff is an evaluation machine that uses a visible light source, so 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 an Ag film of 30 nm. Also, the size of the float glass with a thickness of 3 mm used in the optical measurement was changed to □ 10 cm×10 cm. Otherwise, samples were prepared in the same manner and used for measurement.
This method makes it possible to measure reflection distribution using visible light, and to evaluate reflection directivity.
In the measurement, the near-infrared upward reflectance was measured at a vertical angle (θ) from 20 degrees from the normal direction to the surface of the measurement sample. The azimuth angle (φ) of the incident sample is set to φ=0 deg, which is the direction in which the upward reflection performance of the sample is most efficiently expressed, and which is rotated 90 deg from the ridgeline direction of the triangular prism of the first optical layer, and is further 15 deg. The direction of rotation was set to φ15deg.
From the reflection intensity distribution, the highest intensity value (peak reflection intensity) excluding specular reflection is read, and the highest intensity value (peak reflection intensity) excluding specular reflection of the triangular prism of Comparative Example 3-1 described later is obtained. The relative value % when the result was taken as 100% was calculated as the local reflection intensity ratio.
The effect of suppressing local reflection was evaluated based on the relative value of the highest intensity value excluding this specular reflection.

<State of local reflection>
The state of the distribution of reflected light obtained when the reflection directivity was measured by the aforementioned MiniDiff manufactured by Light Tec was evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
・×: Light that is obliquely incident on the surface of the optical body is reflected in a straight line from the reflecting part, and has a local bright spot ・○: Light that is obliquely incident on the surface of the optical body is reflected Light is reflected non-linearly from the part, and the bright spots are band-shaped or divided into multiple parts to alleviate local bright spots.

<Appearance evaluation of bright lines>
The optical body was attached to a float glass of □ 15 cm×15 cm with a thickness of 3 mm via an adhesive material, and a small light source was irradiated from 15 cm above the optical body to observe the appearance.
The visibility of bright lines was evaluated according to the following evaluation 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 becomes very thin from the bright point of the light source to the edge of the float glass, making it difficult to see.

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

(Example 15-1)
In Example 14-1, an optical body was produced in the same manner as in Example 14-1, except that the master disk 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 disk processing specifications Average shape interval (distance between valleys of adjacent structures): 67 μm
Average shape height (AH): 31 μm
Section base angle - D1: 35deg
Section base angle -D2: 55deg
Height amplitude in extension direction (A): 21 μm
Height modulation in extension direction: sine wave Cycle of sine wave (Pe): 800 μm
Deviation (phase) with adjacent structures (ΔPh): 1/2 period Processing to give the height modulation a phase of 1/2 cycle)

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

(Comparative Example 3-1)
In Example 14-1, the master disk processing specifications were changed as follows, and the master disk was processed so that structures with extended triangular cross sections were arranged side by side as shown in FIG. 3D. Example 14-1 An optical body was prepared and evaluated in the same manner.
・Material disk processing specifications Shape interval (distance between valleys of adjacent structures): 67 μm
Shape height: 31 μm
Section base angle - D1: 35deg
Section base angle -D2: 55deg

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

<For 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, as in Comparative Examples 3-1 to 3-15, visible light transmittance, reflectance, Haze value, shielding coefficient, near infrared rays Similar performance was obtained for the upward reflectance.

<< Reflection Directivity (Local Reflection Suppression) >>
In Comparative Examples 3-1 to 3-15, the reflected light is reflected on a local line without scattering, whereas Examples 14-1 to 14-15 and Examples 15-1 to 15- It was confirmed that local reflection was suppressed in No. 15.
Further, from the distribution of the 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 the same incident angle was set to 100%. From the intensity ratio of the local reflection with the relative value of the reflection intensity at the highest intensity value excluding the specular reflection in the body, it can be seen that the local reflection is suppressed in the optical body of the present invention.
In addition, the bright line generated when the light source is irradiated due to the regular structure, in the optical body of the present invention, which has a reflective structure whose height is modulated in the extending direction of the structure, is in Comparative Example 3 -1 to 3-15 are suppressed.

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

REFERENCE SIGNS LIST 10 optical body 11 first optical layer 12 inorganic layer 13 second optical layer 14 first substrate

The present invention relates to a heat ray reflecting optical body.

Claims (5)

a first optical layer having a convex surface in which a plurality of columnar convex portions 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 such that the convex shape is buried;
has
An optical body, wherein the convex shape satisfies at least one of the following (1) to (4).
(1) In each columnar protrusion, the height changes in the extending direction.
(2) In each columnar protrusion, the apex meanders in a direction perpendicular to both the extending direction and the height direction of the protrusion.
(3) The heights of adjacent columnar protrusions are different.
(4) A triangular prism-shaped convex portion is adjacent to a columnar convex portion having a curved surface. The optical body according to claim 1, wherein the inorganic layer is a wavelength selective reflective layer. The optical body of Claim 1, wherein the inorganic layer is semi-transparent. 4. The optical body according to any one of claims 1 to 3, wherein the first optical layers and the second optical layers are transparent. 5. The optical body according to any one of claims 1 to 4, which is used by being attached to a windowpane.

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