JP2002333514A - Reflector with wide observation angle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflector with wide observation angle in which the direction of the effective reflected light can extremely easily be controlled in a specified observation angle range while the wide observation angle property is maintained and which is especially effective as constitutional parts of a brightly visible image display sheet. SOLUTION: The reflector with wide observation angle is provided with base layer having the top face and the back face surface and a plurality of minute convex mirrors arranged adjacently to each other on the top face of the base layer and having convex faces where a first reflection film is adhered. In this reflector, a plurality of minute concave mirrors having concave faces recessing from the top face to the back face of the base layer and having a second reflection film adhered to the concave faces are arranged on the base layer in such a manner that the minute concave mirror is arranged between the minute convex mirrors adjacent to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved wide-viewing angle reflector having a base layer and a plurality of micro-convex mirrors arranged adjacent to each other on the surface of the base layer. The wide-viewing angle reflector of the present invention is preferably a series of a plurality of beads (microspheres) partially embedded in a base layer or a bonding layer included in the base layer and arranged substantially in a single layer. Is used to form an uneven reflection surface. When such a reflector includes a sheet-shaped base layer or a bonding layer, it is used as a wide-observation-angle reflecting sheet, for example, in an external illumination system (an illumination system using external illumination light), and is used for signs, guidance, and advertisement. This information is useful as a component of an image display sheet that displays information such as images in a prominent manner.

[0002]

2. Description of the Related Art Heretofore, a reflector called a retroreflective sheet has a good visibility at night.
It has been effectively used to form a reflective surface on a sign such as a guide sign. The retroreflective sheet that has been used for a long time is usually designed to shine brightest at a low observation angle, such as an observation angle of about 0.2 to 1 degree, and an observer such as a driver can observe the sign. The reflecting surface can be viewed well even from a relatively distant position. This is because the observer is usually in the low observation angle range as described above when the observer is located relatively far away.
However, when approaching a short distance from the retroreflective sheet, the observer is located outside the observable observation angle range, which makes it difficult to recognize the sign information as compared to observation from a distance. there were. From such a background, it is desired to provide a reflection sheet having a wide observation angle that can be visually recognized, that is, a so-called wide observation angle reflection sheet, and several types have been proposed so far.

As one of such wide observation angle reflection sheets, there is one disclosed in Japanese Patent Application Laid-Open No. 7-281014 proposed by the present inventors. The reflection sheet disclosed in this publication is a capsule lens type or exposure lens type reflection sheet using at least two kinds of glass beads having different refractive indexes and widening the observable observation angle to 20 degrees.
The reflection sheet proposed in the above publication has an observation angle of 1
10 CPL (candela / lux / m ² ) in the range of up to 3 degrees
As described above, 1 CPL or more is possible in the range of the observation angle of 8 to 20 degrees. Such a wide-observation-angle reflecting sheet can make a sign stand out so that it can be easily viewed from a long distance and a short distance, and is widely used especially in a road sign combined with an external light source. I have. However, on the other hand, a reflective sheet having a wider observation angle has been desired as a reflective sheet for a sign.

In the above-mentioned wide observation angle reflection sheet and the conventional retroreflection sheet, glass beads and a reflection film such as a metal deposition film are effectively used. The glass beads are used as a lens, and the reflection film is arranged along a spherical surface (focal plane) including the lens focal point. As a result of the study by the present inventors,
It was concluded that it was difficult to further widen the observation angle with such a configuration.

Accordingly, as a result of further study by the present inventors, a convex curved surface which is fixedly arranged at one end adjacent to each other and swelled from one end to the other on a basic surface such as a base layer surface. A plurality of micro-convex mirrors formed from a plurality of convex portions having a convex surface and a reflective film adhered to the convex curved surface of the convex portions are arranged in a horizontal direction to form a reflective surface of the entire sheet extending over a horizontal plane. It turned out to be effective. Such a reflection sheet using only a plurality of minute convex mirrors is already known, and is disclosed, for example, in Japanese Patent Application Laid-Open No. H11-326609. The reflection sheet disclosed in this publication has a binder layer (binding layer) having an average particle size of 5 to 150 μm on one surface of a support.
It is characterized by having a layer of beads (or irregular shaped particles) of m and a reflective film layer composed of a vapor deposited film in this order. That is, the reflection sheet includes a plurality of beads that are arranged in a single layer adjacent to each other on the surface of the bonding layer, partially embedded in the bonding layer, and the remaining portion is exposed from the bonding layer, The exposed portion of the bead is covered with a reflective film, and the hemispherical surface (convex curved surface) of the bead covered with the reflective film forms a plurality of minute convex mirrors.

The beads usually have a particle size of 50-9.
0% is buried in the binder layer. In such a reflection sheet, the deposited film layer is directly adhered to the exposed portion of the bead, or a resin solution is applied to the exposed surface of the bead in a thin film thickness that does not impair the shape of the exposed glass sphere and dried. After solidification, the deposited film layer is brought into close contact with the resin film. That is, the surface of the vapor-deposited film layer is a reflective surface having the same shape as the concavo-convex shape formed by connecting the exposed portions of the plurality of beads adjacent to each other. This makes it possible to make the most of the diffusion effect exerted by the combination of the plurality of micro-convex mirrors, and to greatly widen the observation angle that can be visually recognized.

Japanese Patent Application Laid-Open No. 61-3129 discloses a diffuse reflection sheet similar to the above, in which a reflection film is disposed on a hemispherical surface of a plurality of beads arranged in a single layer and a plurality of minute convex mirrors are formed. Have been. The reflection sheet disclosed in this publication is used as a diffuse reflection screen for a projection device such as a video projector.

US Pat. No. 4,712,867 discloses that
A reflector including a base layer having a convex curved surface and a concave curved surface is disclosed. The reflector disclosed herein has a plurality of convex curved surfaces arranged adjacent to each other on the surface of the base layer, and a plurality of concave curved surfaces depressed from the surface of the base layer toward the back surface, and the concave curved surface is They are arranged between adjacent convex curved surfaces. The base layer itself, i.e., the binder and the plurality of glass microspheres dispersed in the binder so that the convex curved surface and the concave curved surface themselves do not have reflectivity and cover the convex curved surface and the concave curved surface. A reflective coating layer is included. The glass microspheres are completely embedded in the coating layer, and the coating layer follows the shapes of the convex curved surface and the concave curved surface,
They are in close contact with the convex and concave surfaces. The dimensions (height and depth) of the convex curved surface and the concave curved surface are considerably larger than the diameter of the glass microsphere. In this type of reflector, a wide range of incident angle light can be reflected by effectively utilizing the undulation (irregular shape) of the reflecting surface and the diffuse reflectivity of the glass microspheres embedded in the coating layer.

[0009]

However, if only a plurality of micro-convex mirrors as described above are used, when the arrangement density of the micro-convex mirrors is low, most of the reflected light is only diffused and there is almost no reflection directivity. However, the direction of the effective reflected light cannot be controlled so as to reflect as strongly as possible in a predetermined observation angle range. In addition, when the arrangement density of the minute convex mirror is increased, the reflection directivity can be somewhat improved, but the luminance is reduced. Although the reason for such a decrease in luminance is not clear, the following causes can be considered.

[0010] Increasing the arrangement density of the micro-convex mirrors means that the distance between adjacent beads becomes smaller, and the beads become denser. At this time, a dent is formed between adjacent beads (between exposed portions of the beads), and the dent has a shape that tapers from the top of the bead toward the bonding layer. Such a tapered shape becomes narrower (narrower) as it goes further (closer to the bonding layer). Also, the tapered tip (the bottom of the depression) is usually flat because it is the surface of the bonding layer. Therefore, it is considered that light incident on such a dent hardly forms observable reflected light, and the reflected luminance is reduced.

On the other hand, in the reflector disclosed in US Pat. No. 4,712,867 having a convex curved surface and a concave curved surface, the coating layer containing glass microspheres has no specular reflectivity and strongly reflects incident light. Therefore, it was difficult to increase the reflection luminance. Also, because these convex and concave surfaces have rather large dimensions, they do not function as minute convex mirrors and minute concave mirrors. Further, since the glass microspheres embedded in the coating layer on the concave curved surface tend to diffusely reflect incident light, it is difficult to enhance the reflection directivity on the concave curved surface. Therefore, the direction of the effective reflected light could not be controlled.

In view of the above, a reflective sheet which is bright (ie, with high luminance) within a predetermined and effectively widened observation angle range, which is the original background for which a wide observation angle reflection sheet is desired to be provided, has been proposed. In order to provide the present invention, the present inventors have further studied based on a reflection sheet having a plurality of minute convex mirrors, and have accomplished the present invention. That is, an object of the present invention is to control the direction of effective reflected light within a predetermined observation angle range while maintaining a wide observation angle property, and it is very easy to control the direction of the effective reflected light. It is an object of the present invention to provide a wide observation angle reflector particularly useful as a component of an image display sheet used as a signboard or the like.

[0013]

In order to solve the above-mentioned problems, the present invention is directed to a base layer having a front surface and a back surface, and a first reflection film which is disposed adjacent to each other on the surface of the base layer and is in close contact with each other. A plurality of minute convex mirrors having a convex curved surface, in a wide observation angle reflector, in the base layer,
The base layer has a concave curved surface that is depressed from the front surface to the back surface, and the concave curved surface is provided with a plurality of minute concave mirrors to which a second reflective film is in close contact, and the minute concave mirror is provided with the minute minute mirrors adjacent to each other. A wide viewing angle reflector is provided between the convex mirrors.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Operation] A wide observation angle reflector according to the present invention has a plurality of minute convex mirrors as well as a plurality of minute concave mirrors which are not provided with a conventional reflection sheet, like the conventional one. Have. In the reflector having such a configuration, in addition to the diffusion effect of the micro-convex mirror, the directivity of the micro-concave mirror can be improved, and the effective reflected light (reflected light that can be viewed with high brightness) can be obtained while maintaining a wide observation angle. It is extremely easy to control the direction of ()) within a predetermined observation angle range.

One preferred embodiment of the wide observation angle reflector of the present invention has the following configuration, and a micro convex mirror and a micro concave mirror are effectively combined. That is, the wide observation angle reflector includes (A) a base layer having a front surface and a back surface,
(B) on the surface of the base layer, a plurality of convex portions having a convex curved surface fixed at one end adjacent to each other and bulging from one end to the other end; and (C) closely contacting the convex curved surface of the convex portion. A first reflection film. Further, in the wide-viewing-angle reflector of this mode, a concave curved surface depressed from the surface of the base layer toward the rear surface is disposed between the adjacent convex portions, and the second reflective film adheres to the concave curved surface. It is characterized by doing. According to such a configuration, the depressions between adjacent protrusions (between exposed portions of the beads when buried beads are used) are effectively used as a reflection surface, and a reduction in luminance is effectively prevented. Can be prevented.

The function of the convex curved surface and the concave curved surface will be described in more detail. The convex curved surface on which the first reflective film is in close contact functions as a plurality of minute convex mirrors. On the other hand, the second
The concave curved surface on which the reflective film is in contact functions as a plurality of minute concave mirrors. In the reflector having the above configuration, such a small convex mirror and a small concave mirror are alternately connected to each other over a horizontal plane,
It constitutes the reflecting surface of the entire reflector. Therefore, in addition to the diffusion effect of the micro-convex mirror, the directivity improvement effect of the micro-concave mirror is obtained, and it is extremely easy to control the direction of the effective reflected light within a predetermined observation angle range while maintaining a wide observation angle. Become.

The surface roughness of the uneven reflecting surface formed by connecting the first reflection film and the second reflection film to each other depends on the effect of widening the observation angle (mainly due to diffuse reflection) and the effect of controlling the observation angle ( It is preferably determined so as to balance the effect of enhancing directivity. For example, the ratio of the average roughness of the concave mirror (D: unit μm) to the average interval of the convex mirror (P: unit μm) is the ratio of the surface roughness of the uneven reflection surface formed by the first reflection film and the second reflection film connected to each other. The value represented by (D / P) is preferably in the range of 0.02 to 0.25. If the surface roughness is too large, the diffusion effect is reduced, and the wide observation angle may be reduced. Conversely, if the surface roughness is too small, the directivity is reduced and the observation angle control effect is effectively increased. May not be possible. From such a viewpoint, the range of the roughness is preferably 0.04 to 0.20, particularly preferably 0.05 to 0.18. Note that D and P
Is a value measured using a laser three-dimensional roughness meter or a laser microscope equipped with a three-dimensional roughness meter, and is defined as follows. The average depth of the concave mirror is parallel to the base layer including the deepest point of the concave curved surface (small concave mirror) covered with the reflective film and the vertex of the convex curved surface (small convex mirror) covered with the reflective film surrounding the concave surface. This is the average distance from the plane. The average depth of the concave mirror is randomly determined by a predetermined number (for example, 10
(Or more) micro-concave mirrors and all the micro-convex mirrors (usually 3 or 4) surrounding the micro-concave mirror can be selected and averaged over the distance defined above. The average distance between the convex mirrors can be determined by taking a laser microscope photograph of the measurement sample and averaging the distance between predetermined numbers (for example, 30 to 50) of adjacent convex mirrors measured on the photograph.

It is preferable that the reflection sheet provided with the minute convex mirror and the minute concave mirror as described above has a structure formed using, for example, the following beads (microspheres). That is, the wide-observation-angle reflector is (a) a bonding layer having a front surface and a back surface, and (b) fixed adjacent to each other on the surface of the bonding layer and partially embedded in the bonding layer.
A plurality of beads, the rest of which are exposed from the tie layer,
(C) a first reflective film for coating the beads,
(I) covering the exposed portions of the plurality of beads and filling a space between the exposed portions of the beads adjacent to each other;
A coating layer having a predetermined thickness is disposed, and (ii) the coating layer covering the exposed portions of the beads forms a convex portion having a convex curved surface bulging in a direction from the bonding layer toward the coating layer;
The first reflection film is in close contact with the convex curved surface that is the coating layer surface, and (iii) a surface of the coating layer that is recessed from the coating layer surface toward the bonding layer between the adjacent convex portions. And a second reflective film is in close contact with the concave curved surface.

In such a structure, the above-mentioned micro convex mirror can be formed by effectively utilizing the plurality of exposed surfaces of the beads partially embedded in the bonding layer. In addition, by controlling the thickness of the coating layer covering the exposed surface of the beads, the curvature of the convex curved surface (small reflection surface) can be controlled, and it is easy to balance the effect of widening the observation angle and the effect of controlling the observation angle. is there.

On the other hand, the surface of the bonding layer between a plurality of adjacent beads exposed from the bonding layer is usually flat. Therefore, a reflection film (second reflection film) is provided between the beads.
Even if it is provided as it is, no minute concave mirror is formed, so that the observation angle control action cannot be enhanced. Therefore, the coating layer is also arranged in the gap between the beads, a concave curved surface formed of the coating layer surface is formed, a second reflection film is provided here, and a minute concave mirror is formed. Further, by controlling the thickness of the coating layer that fills the space between beads, the curvature of the concave curved surface (small reflection surface) can be controlled, and it is easy to balance the effect of increasing the observation angle and the effect of controlling the observation angle. . In the present specification, the term "concave curved surface" is a surface having a shape that functions as a concave mirror if a reflective film is provided thereon, and a surface curved to have a bowl-like or parabolic shape. Means

The coating layer is usually a layer formed by applying a liquid containing a resin and solidifying it. The solidification includes curing of the reactive liquid (including polymerization and crosslinking), drying by evaporating the solvent contained in the liquid, cooling of the molten liquid to solidify, and the like. The thickness of the coating layer is usually determined so as to have a predetermined ratio to the diameter (average diameter, D) of the beads. The ratio (t / D) of the thickness (t) of the coating layer to the diameter (D) of the beads is usually 0.14 to 0.1.
42, preferably in the range of 0.20 to 0.30. If the coating layer with respect to the bead diameter is too thin, a micro concave mirror cannot be formed, and the observation angle control action may not be effectively enhanced. Conversely, if the coating layer is too thick, the radius of curvature of the micro convex mirror becomes too large. The diffusion effect may be reduced, and the wide observation angle may be reduced.

(Reflector) A preferred example of the reflector of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing a cross section of a reflector according to the present invention. FIG.
FIG. 4 is an enlarged view showing a cross section of the reflector according to the present invention in detail. The reflector (10) has a front surface and a back surface, and a support (1) formed in a sheet shape, and a bonding layer (2) fixedly disposed on a surface (11) of the support (1). And The bonding layer (2) is usually formed by coating a layer containing a polymer on a support, and the back surface (22) that is in close contact with the support and the front surface (2) in which a plurality of beads (3) are embedded.
1). In FIG. 2, the support (1) is omitted.

On the surface of the bonding layer (2), a plurality of beads (3) are partially buried in the bonding layer (2) and arranged next to each other. As shown, the beads (3)
It has a portion (32) buried in the bonding layer and an exposed portion (31) exposed from the bonding layer. Further, a coating layer (4) having a predetermined thickness is arranged so as to cover the exposed portions (31) of the beads and fill the space (33) between the exposed portions of the beads adjacent to each other. The coating layer is preferably formed by applying a liquid containing a resin and solidifying it as described above.
In this way, a base layer (5) composed of a laminate including the support (1), the bonding layer (2) and the coating layer (4) is formed. Further, a part of the plurality of beads (3) is embedded in the base layer (5), the remaining part of the beads (3) protrudes from the base layer (5), and the protruding part is covered with a coating layer (4). A plurality of projections (6) formed by effectively utilizing the three-dimensional shape of the coating layer (4) are fixed to the base layer (5). As shown, the convex portion (6) has a convex curved surface (61) bulging outward from the surface of the base layer (5).
Having.

The radius of curvature and dimensions of the convex curved surface (61) are appropriately selected from the diameter of the buried beads, the burying depth of the beads, the thickness of the coating layer (dry thickness), the thickness of the resin liquid applied, and the like. Can be determined. For example, the diameter (average diameter) of the embedded beads is usually 55 to 2,000 μm, preferably 60 to 1,000 μm, and particularly preferably 70 to 500 μm.
μm. If the diameter of the beads is too large, the diffusion effect is reduced, and the wide observation angle may be reduced. Conversely, if the diameter of the beads is too small, the space between the exposed portions of the beads adjacent to each other is too small, and it is difficult to form an effective concave surface. As a result, the directivity is reduced and the observation angle control action is effectively enhanced. May not be possible.

When the diameter of the beads has a certain range of variation, it is easy to enhance the diffusion effect and improve the wide observation angle. From such a viewpoint, the variation in the diameter of the beads is usually 3 to 25%, preferably 5 to 20% with respect to the average diameter of the beads. If the variation in the bead diameter is too large, the observation angle control action may not be effectively enhanced.

The burying depth of the beads (the length in the diameter direction of the buried portion) is usually 20 to 70%, preferably 30 to 60%, based on the diameter of the beads. If the burying depth of the beads is too shallow, the diffusion effect will decrease, and the wide observation angle may decrease.On the contrary, if the burying depth is too deep, the directivity decreases,
There is a possibility that the observation angle control action cannot be effectively enhanced.

On the other hand, between the adjacent convex portions (6), a concave curved surface (510) is formed which is recessed from the front surface (51) of the base layer (5) toward the rear surface (52). As described above, the concave curved surface (510) forms a surface tension of the resin liquid while the resin liquid applied to fill the space (33) between the exposed beads (31) adjacent to each other solidifies. It is a depression formed into a curved surface as shown in the figure by physical action.

For example, when substantially all of the beads are substantially regularly arranged so as to be located at the intersection of two straight lines of the grid virtually drawn on the surface of the base layer, the square ( One depression is formed at the center of the four beads located at the apex of the rectangle). This depression has a substantially circular shape in a horizontal plane parallel to the surface of the base layer. In FIG.
The surface of this depression forms a concave curved surface (510). The concave curved surface and the convex curved surface formed using the coating layer are connected to each other to form an uneven surface. After the reflective film (7) is formed, the uneven reflective surface having a predetermined surface roughness is formed. To form

When two adjacent beads are not in contact with each other along one side of the square, a depression (not shown) is also formed between these beads. The concave surface of the depression on this side is usually connected to the concave surface of the central depression. In such a case, the concave curved surface on this side can also be used as a minute concave mirror after the reflection film is formed.

The arrangement of the beads is not limited to a grid-like arrangement (rectangular arrangement). For example, beads are arranged at each of four vertexes of a non-rectangular parallelogram, and the center of a plurality of beads arranged as such is arranged. May be provided with a concave mirror. The bead arrangement may be a mixture of a rectangular arrangement and a parallelogram arrangement. Furthermore, it may include partially irregular portions, and in addition to these square arrays, there are also triangular and pentagonal arrays, and concave mirrors may be arranged at the centers of three or five beads, respectively.

The radius of curvature and the depth of the concave curved surface (510) are determined by the thickness of the coating layer (dry thickness), the thickness of the resin liquid applied, the rheology of the resin liquid, and the solidification conditions of the resin liquid (drying temperature and drying time). Etc.) and the shape or size of the space (33) can be determined by appropriate selection. However, if the thickness of the coating layer is too thin, no curved depression is formed. Therefore, usually, the thickness of the coating layer is preferably controlled in the above range.

The thus formed convexly curved surface (61) and concavely curved surface (510) are integrally covered, and a reflection film (7) is formed so as to be in close contact with those curved surfaces. This allows
Each is composed of a reflective film (7), and has a convex curved surface (6).
1) a first reflective film (71) closely contacting the concave surface (51);
A second reflective film (72) is formed in close contact with 0). The convex portion (6) to which the first reflective film (71) adheres forms a reflective convex portion (60) having a micro convex mirror. Second reflection film (7
The concave curved surface (510) to which 2) adheres functions as a minute concave mirror.

The reflection film (7) is usually a film containing a substance having metallic luster such as metal. Such a metallic luster film is
For example, as shown in FIG. 2, a metal film having a relatively small thickness formed by a thin film forming method such as evaporation or sputtering.
Further, as shown in FIG. 1, a metallic glossy coating layer formed from a metallic glossy paint containing a polymer capable of forming a film and metallic luster particles such as a metal dispersed in the polymer may be used. In addition, when the thickness of the metal film is relatively thick, and the metal film directly disposed on the surface of the bonding layer in which the beads are embedded can form an effective convex curved surface, the reflection film also serves as the coating layer,
The coating layer of the resin liquid may be omitted.

Each reflection film (71, 72) has a predetermined radius of curvature. The radius of curvature of the convex curved surface is not particularly limited as long as the effects of the present invention are not impaired.
５5 mm, preferably 50 μm〜2 mm. The radius of curvature of the concave curved surface is not particularly limited as long as the effects of the present invention are not impaired, but is usually 15 μm to 5 mm, preferably 40 μm.
m to 3 mm.

On the other hand, other dimensions of each of the above-mentioned elements constituting the reflector of the present invention are not particularly limited as long as the effects of the present invention are not impaired. The distance (pitch, P) between adjacent convex portions is usually 30 to 3,000 μm, preferably 60
〜1,000 μm, particularly preferably 70-500 μm. When beads are used for forming the convex portions, it is preferable that adjacent beads do not contact each other in order to make the pitch as large as possible within the above range, though it depends on the diameter of the beads.

The depth (D) of the concave surface is usually 2 to 600 μm.
m, preferably 5 to 300 μm. The thickness of the coating layer is
Usually, it is 5 to 300 μm, preferably 10 to 200 μm. The thickness of the tie layer is usually 20-500 μm, preferably 30-250 μm. The thickness of the support is usually 20 to
It is 2,000 μm, preferably 30 to 1,000 μm.

(Method of Manufacturing Reflector) The reflector of the present invention comprises:
It can be manufactured in various ways. For example, the reflector (10) having the structure shown in FIG. 1 or FIG. 2 is usually manufactured as follows. First, a support (1) is prepared.
The support (1) is used to support the tie layer (2) and increase the mechanical strength of the base layer (5) so as to prevent breakage of the tie layer during the manufacturing process. When using a reflector, if the strength of the entire reflector is sufficient for use,
After completion of the reflector, the support (1) may be removed from the reflector (10).

The support (1) is a film or sheet made of, for example, a polymer material or paper. When the reflector is removed from the reflector after completion, the surface (1) of the support (1) is removed.
1) is preferably subjected to a peeling treatment so as to be easily peeled from the bonding layer (2). On the other hand, when the reflector (11) is not removed from the reflector even after completion of the reflector, the surface (11) of the support (1) is easily adhered by corona treatment, primer coating, or the like in order to increase the adhesive strength with the bonding layer (2). It is good to apply processing. The polymer used for forming the support is, for example, polyester (PET, PEN, etc.), acrylic polymer, vinyl chloride polymer, polyolefin copolymer (ethylene-acrylic acid copolymer, ionomer, etc.), polyurethane, etc. .

Next, the bonding layer (2) is arranged on the surface (11) of the support (1). The bonding layer (2) is preferably a polymer layer containing a polymer capable of adhering and holding the beads. Such a polymer layer can be formed, for example, by applying a polymer-containing coating material on a support and solidifying it. Further, a molded film containing a polymer may be laminated on a support by an extrusion molding method. The polymer used for the bonding layer is, for example, acrylic polymer, polyurethane, polyester, vinyl chloride polymer, polyolefin copolymer (ethylene-acrylic acid copolymer, ionomer, etc.).

Subsequently, a plurality of beads (3) are partially embedded in the bonding layer (2). Beads are generally spherical particles made of materials such as glass, ceramics, hard polymers, metals, metal oxides, and the like.

For embedding the beads (3), for example, a coating material for forming the bonding layer (2) is applied on a support, and before the coating material solidifies, a plurality of beads (3) are dispersed in a single layer. Do it. In this way, the beads are partially submerged in the paint before solidification, and then the paint is solidified. The solidification of the paint can be carried out by heating and drying when the paint contains a solvent. If the tie layer contains a melted or thermosoftened polymer, the beads are partially submerged and then the tie layer is cooled (including natural cooling) to complete the embedding of the beads. Further, in order to increase the embedded ratio of the beads (the ratio of the embedded portion to the bead diameter) as much as possible, the bonding layer can be heated after the beads are dispersed.

Further, as well known in the field of retroreflective sheeting, beads may be embedded by using a process base having a polyethylene layer on the surface thereof in the following manner. First, beads are arranged in a single layer on the polyethylene layer of the process base material, and are partially embedded in the polyethylene layer. The coating material for the bonding layer as described above is applied so as to cover the bead layer having a portion exposed from the surface of the polyethylene layer, and dried. After drying, the process substrate is removed to obtain a binding layer having a partially embedded bead layer having an exposed portion.

After the embedding of the beads (3) in the bonding layer (2) so as to have an exposed portion is completed according to any one of the above methods, a predetermined surface is formed on the surface (21) of the bonding layer (2). The resin liquid is applied with a coating thickness of and then solidified to form a coating layer (4). The resin of the coating layer contains, for example, a polymer such as an acrylic polymer, a polyurethane, a polyester, a vinyl chloride polymer, and a polyolefin copolymer (ethylene-acrylic acid copolymer, ionomer, etc.).

Finally, a reflecting film (7) is adhered to the surface of the coating layer (4) formed as described above to complete the reflector of the present invention. As described above, a metallic luster material is used as the material of the reflection film (7). As such a metallic luster material, for example, aluminum, silver, nickel, chromium or the like is used. The thickness of the reflection film is selected so that the reflectance of the reflection film is as high as possible, and is usually 200 Å or more, preferably 400 Å or more.

The reflector of the present invention can be formed without using a coating layer as described above. As shown in FIG. 3, on the surface (51) of the base layer (5), a plurality of projections (6) composed of partially embedded first beads (30) and second beads (39). This is a method for forming a concave-convex structure composed of a plurality of depressions (511) composed of traces of the holes. If, for example, a metal deposition film is directly adhered to the uneven surface of the structure formed in this way, an uneven reflecting surface having a predetermined three-dimensional surface roughness can be formed.

To form such an uneven structure on the base layer, for example, the following method can be adopted. First, a base layer (5) containing a polymer having thermoplasticity is prepared. In a state where the base layer (5) is heated and softened, the plurality of first beads (3) and the plurality of second beads (39) are placed on the base layer surface (51) at the exposed portions of each bead. Are partially buried in the base layer (5) so that the positions of the tops are substantially the same level. At this time, the second beads (39) having a relatively small diameter are buried shallowly and are easily detached from the base layer, and the first beads (3) having a relatively large diameter are buried deeply and are easily buried. Fixed to 5). After the two kinds of beads are embedded in the base layer (5) in this manner, the second beads (39) are removed to form a concave curved surface (510) consisting of the surface of the depression (511). .

The removal of the second beads is performed using, for example, electrostatic suction or reduced pressure suction, and the second beads are selectively removed while leaving the plurality of first beads on the base layer. Moreover, you may remove mechanically using a brush etc. Alternatively, beads made of a magnetic material may be used as the second beads, combined with the non-magnetic first beads, and the second beads and the second beads may be selectively removed using magnetic attraction.

The reflector of the present invention can be formed without using the burying of beads as described above. For example, as shown in FIG. 4, as a negative corresponding to the uneven structure to be formed on the surface (51) of the base layer (5), a replication method using a negative mold (8) having a plurality of unevenness is used. . The curable polymer is brought into contact with the irregularities so as to fill the irregularities of the negative type (8), and is cured in a state. Alternatively, the polymer melted or softened by heating is brought into contact with the irregularities of the negative type (8), and then cooled and solidified. After the curing or solidification of the polymer, when the negative mold is removed, the positive irregularities corresponding to the negative irregularities are duplicated on the base layer surface (51).
Thereby, each is integrally fixed to the base layer surface (51), each has a convex curved surface (61), and a plurality of convex portions (6) arranged adjacent to each other and a convex portion adjacent to each other. A concave surface (510) formed therebetween can be formed. The reflecting film (7) is brought into close contact with the surface (51) on which the concavo-convex structure is formed as described above, whereby the reflector of the present invention can be manufactured.

The negative mold (8) is preferably formed, for example, by subjecting a metal plate to an unevenness forming process such as electric discharge machining. As the curable polymer, one containing an oligomer or monomer which can be cured usually by heat or radiation (ultraviolet rays, electron beams, etc.) can be used. For example, those containing an acrylic monomer or oligomer are preferred. Polymers that can be melted or softened include polymers such as acrylic polymers, polyurethanes, polyesters, vinyl chloride polymers, polyolefin copolymers (ethylene-acrylic acid copolymers, ionomers, etc.), and polyamides. it can.

The reflector of the present invention can also be formed by a method combining the above-mentioned duplication method with a method of forming a concave-convex curved surface using a coating layer (coating layer method).
For example, as shown in FIG. 6, a base layer precursor (53) having a convex precursor (54) integrally bonded to the surface.
Is prepared, and a resin liquid as described above is applied to the surface of the base layer precursor (53), and solidified to form a coating layer (4) having a predetermined thickness. As a result, similarly to the case where the above-described bead embedding is used, the convex portion (6) having the predetermined convex curved surface (61) and the predetermined concave curved surface (5) are formed on the surface of the coating layer (4).
10) can be formed.

That is, according to such a method, the base layer precursor (53) having the plurality of convex precursors (54) integrally bonded to the surface, and the convex precursor (54) is coated. And a coating layer (4) arranged so as to have a predetermined thickness so as to fill a space (55) between the convex precursors (54) adjacent to each other, and the base layer (5) , A base layer precursor (53) and a coating layer (4), and the convex portion (6) comprises a convex portion precursor (54) and a coating layer (4) covering the same, and has a concave curved surface (510). ) Can easily form the reflector precursor (101) consisting of the surface of the coating layer which fills the space between the convex precursors (54). Then, a reflecting film can be adhered to the uneven surface of the reflector precursor (101) in the same manner as in the other methods described above, and the reflector can be completed.

According to such a method, it is possible to easily change the size and shape of the uneven reflection surface by controlling the thickness and the like of the coating layer without changing the size and shape of the negative type unevenness. The direction of the effective reflected light can be controlled very easily within a predetermined observation angle range. That is, reflectors having different reflection characteristics can be easily formed using one negative type.

The base layer precursor as described above can be prepared not only by the above-described duplication method but also by an embossing method. That is, the base layer sheet having no convex precursor,
Embossing can be performed using a negative mold having predetermined irregularities on the surface to form a base layer precursor having a convex precursor formed integrally with the surface. In the embossing method, it is relatively easy to reduce the molding time (time for forming irregularities on the base layer sheet) as compared with the duplication method. on the other hand,
In the embossing method, as in the replication method, it is easier to make the arrangement of the convex portions regular than in the bead embedding method. Therefore, a reflector formed by combining the embossing method and the coating layer method is suitable for accurately controlling the direction of the effective reflected light within a predetermined observation angle range. In addition, during embossing, the surface properties of the positive unevenness transferred to the base layer side are reduced, and when a reflective film is formed directly on the positive unevenness transferred as it is, the surface property of the reflective surface is reduced. However, the reflection luminance may be reduced. However, if the reflective film is formed on the coating layer covering the surface of the positive unevenness on the base layer side, such a decrease in the surface properties of the reflective surface can be effectively prevented.

The base layer sheet used in the embossing method can be formed from a material that can be easily plastically deformed by pressurization or by pressurization while heating, such as a metal or a polymer. As the polymer, for example, polyester, acrylic polymer, vinyl chloride polymer, polyolefin copolymer (ethylene-acrylic acid copolymer, ionomer, etc.), polyurethane and the like can be used. The thickness of the base layer sheet is usually 50 μm to 5 mm,
It is preferably in the range of 70 μm to 3 mm. For forming the coating layer, the same resin liquid and coating method as in the case of the above-described bead burying method can be used.

When the above-mentioned duplication method or embossing method is combined with the coating layer method, the surface of the convex precursor of the base layer precursor does not need to have a convex curved surface. Also, the depressions between the adjacent convex precursors need not have a concave curved surface. For example, the base layer precursor (53) of FIG.
In this case, the bottom surfaces of the depressions between the adjacent convex precursors are flat. This is the same as the case of the above-mentioned bead embedding method,
The bottom surface of the depression between the beads is also usually flat before the coating layer is disposed (see FIG. 1 or 2). Even in the case of such a flat depression on the bottom surface, by disposing a coating layer having a predetermined thickness, a concave curved surface composed of the coating layer surface applied to the depression can be easily formed. Similarly, even if the surface of the convex precursor does not have a smooth convex curved surface as shown in FIGS. 7 to 11, a convex curved surface composed of the coating layer surface covering the convex portion is easily formed. it can.

In the example of FIG. 6, a plurality of substantially hemispherical convex precursors are arranged in a grid pattern, that is, a plurality of straight lines arranged vertically and horizontally to form a grid pattern are orthogonal to each other. The convex precursors are regularly arranged on the intersections. As long as the depressions (spaces 55) are arranged between the adjacent protrusion precursors, a portion may be in contact with the periphery of the protrusion precursor. However, as in the example of FIG. 6, it is preferable that the protruding precursors adjacent to each other do not come into contact with each other, and the dents (spaces 55) are arranged so as to surround the periphery of the protruding precursor. This is because the formation of the concave curved surface by the coating layer becomes easy.

The base layer precursor (53) shown in FIG. 7 is the same as that of FIG. 6 except that the shape of the projection precursor (54) is substantially cylindrical. The example of FIG. 8 is the same as that of FIG. 6 except that the shape of the projection precursor (54) is substantially conical. In the example of FIG. 7, the shape of the projection precursor may be a prism, and in the example of FIG. 8, the shape of the projection precursor may be a pyramid.

FIGS. 9 to 11 show some examples particularly suitable for the case where the direction of the effective reflected light is to be particularly easily controlled. In the base layer precursor (53) shown in FIG.
The substantially hemispherical projection precursors (54) obtained by further cutting the substantially hemispherical projections in half are arranged in a grid pattern. As shown in the drawing, the surfaces substantially perpendicular to the surface of the base layer precursor (cut surface: 541) are usually all oriented in the same direction. Thereby, the reflection directivity can be particularly easily increased.
The example of FIG. 10 is the same as that of FIG. 9 except that a substantially semi-conical projection precursor (54) obtained by further cutting the substantially conical projection into half is employed. The example of FIG. 11 is the same as the case of FIG. 9 except that the convex part precursor (54) in which the vertex part of the substantially semi-conical projection is cut off is employed.

In the examples of FIGS. 6 to 11, the shapes and dimensions of the projection precursors are all the same, but a plurality of projection precursors having different shapes and / or dimensions may be employed. Such examples include, for example, the examples shown in FIGS.

FIG. 12 shows an example in which a substantially semi-conical projection precursor (54) obtained by cutting a substantially conical projection in half is arranged in a grid pattern. The inclination angle of the precursor (53) with respect to the surface, and the cut surface (54)
A plurality of protrusion precursors having different directions in 1) are provided. In the illustrated example, the protrusion precursors having the same shape and the same dimensions are arranged along a straight line forming a grid.
In addition, with the central part of the base layer precursor (53) as a boundary, the convex part precursor is divided into two sets in which the cut surfaces (541) face each other. In a reflector produced by a coating layer method using such a base layer precursor, light incident from the zero degree direction near the center is likely to be reflected at a relatively high angle. Therefore, with such a reflector, it is easy to control the directivity such that the reflection luminance in a relatively high observation angle direction is higher than the reflection luminance in a relatively low observation angle direction.

The base layer precursor (53) shown in FIG.
Is an example in which two substantially hemispherical convex precursors (54a, 54b) having different heights and diameters are alternately arranged in a grid pattern. In the example of FIG. 14, the substantially convex first protrusion precursor (5
4a) and the substantially hemispherical second convex precursors (54b) having different heights and diameters from the first convex precursors are alternately arranged in a grid pattern. In the example shown in FIG. 15, the substantially hemispherical first convex portion precursor (54a) and the substantially prismatic second convex portion precursor (54b) are alternately arranged in a grid pattern.
When a plurality of convex precursors having different shapes and / or dimensions are used as described above, the direction in which the effective reflected light can be strongly reflected is widened, and the wide observation angle reflectivity can be easily increased.

In order to enhance the wide observation angle reflectivity, FIG.
As in the example shown in FIG. 6, while using a plurality of protrusion precursors having the same shape and dimensions, the protrusion precursors are formed into a first set and a second set which differ only in the direction from each other. Is also good. In the illustrated example, the convex section precursors (54c, 54c) whose horizontal section (section parallel to the surface of the base layer precursor) has a substantially elliptical shape.
d) is used. These substantially elliptical convex precursors all have the same shape and dimensions, but two sets in which the direction of the major axis of the horizontal section (ellipse) is different from each other,
A first set including the first convex precursor (54c) and a second set including the second convex precursor (54d) having a major axis direction orthogonal to the major axis direction of the first convex precursor (54c). Divided into pairs. When such an effect is expected, it is preferable to use a convex precursor whose horizontal cross section is not a circle or a regular polygon. The protrusion precursor is not limited to the above, and various shapes can be adopted as long as the effects of the present invention are not impaired.

As shown in FIG. 17, a concave portion (56) having a concave curved surface may be formed between adjacent convex precursors (54). In the illustrated example, FIG.
As in the case of No. 0, a substantially semi-conical convex precursor is employed. On the surface of the base layer precursor, concave portions (56) and convex precursors (54) are alternately arranged in a grid pattern. Are located.

In the embossing method, the size of the convex precursor on the surface of the base layer precursor is not particularly limited as long as the effects of the present invention are not impaired. For example, the height of the projection precursor is usually 40 μm to 1 mm, preferably 50 to 600 μm.
It is. The distance between the adjacent convex precursors is determined so that the distance between the convex mirrors formed on the convex surface and the depth of the concave mirror formed after the formation of the coating layer and the reflective film fall within the above-mentioned predetermined range. But usually 40 μm to 4 m
m, preferably 70 μm to 2 mm, particularly preferably 80 μm
１1 mm.

The reflector of the present invention may further have a protective layer made of a transparent coating covering the surface of the reflective film along the irregularities. Such a protective layer has irregularities on its surface due to irregularities of the reflective film. The protective layer can be formed by a method in which a coating solution containing a polymer is applied to the surface of the reflective film and dried to form a coating film, or a method in which a thermoplastic polymer film is adhered while heating. Further, at the time of heating and adhesion, vacuum pressing may be performed.

Examples of the polymer for the protective layer as described above include acrylic polymers, polyurethanes, polyesters, vinyl chloride polymers, polyolefin copolymers (ethylene-acrylic acid copolymers, ionomers, etc.),
Polymers such as fluoropolymers and silicones. Preferably, the polymer is curable by light or heat. The thickness of the protective layer is usually 1 to 100 μm, preferably 3 to 50 μm.

(Image Display Sheet) The wide observation angle reflector of the present invention is useful as a reflection sheet as a component of a reflection type image display sheet, as described above. The reflection type image display sheet is manufactured using the wide observation angle reflector of the present invention, and preferably has, for example, the following configuration. That is, a wide-observation-angle reflector (reflection sheet), a light-transmitting polymer layer disposed so as to cover the convex-curved surface at a predetermined distance from the convex-curved surface of the wide-observation-angle reflector, and its light An image display sheet comprising: a light-transmitting image disposed on at least one of a front surface and a rear surface of a transparent polymer layer. In such an image display sheet, the external illumination light illuminated on the surface (light-transmitting polymer layer) of the image display sheet is reflected by the uneven reflection surface formed by the first reflection film and the second reflection film, The light-transmitting polymer layer and the reflected light transmitted through the image are formed. The reflected light allows the observer to visually recognize the image. Therefore, the image can be satisfactorily visually recognized in a controlled observation angle range as wide as possible, that is, from a relatively long distance or a short distance.

On at least one side of the light-transmitting polymer layer, a light-transmitting image formed of a light-transmitting colored ink is usually arranged. The light-transmitting polymer layer is fixed so that a space is formed between the light-transmitting polymer layer and the uneven reflection surface. The fixing of the light-transmitting polymer layer is usually performed by bonding a joining frame-shaped portion provided along the peripheral edge of the base layer and the peripheral edge of the back surface of the light-transmitting polymer layer. An ordinary adhesive such as an acrylic or epoxy adhesive can be used for the adhesion.

The image display sheet according to the present invention is used as a component such as a sign. Therefore, in order to adhere and fix the image display sheet to an adherend such as a sign substrate, an adhesive layer containing an adhesive or the like is provided on the back surface of the base layer (the back surface (52) of the support or the back surface of the bonding layer). And place
Good to complete as a product.

The light-transmitting polymer layer is usually formed from a film or sheet containing a polymer such as an acrylic, polyester, polyurethane, polyolefin, polyamide or the like. In addition, it is preferable to perform white dot printing on the front surface or the back surface of the light transmitting polymer layer in order to obtain whiteness as a base. This is because the visibility of the light transmissive image can be effectively improved. Further, in order to obtain the same effect, a partially diffused light transmitting film can be used as the light transmitting polymer layer. The thickness of the film or sheet as the light-transmitting polymer layer is not particularly limited, but is usually 10 to 800 μm.
It is.

The light-transmitting polymer layer does not form a space between the uneven surface and the reflecting surface, as described above, and has a back surface having unevenness in close contact with the uneven reflecting surface and a surface on which the light-transmitting image is arranged. May be provided. Also, without using a light-transmitting polymer, directly on the uneven reflection surface, by means such as printing,
A light transmissive image may be formed. Furthermore, using the reflector of the present invention as a projection screen, an image including information on signs and guidance can be projected on the surface of the reflector by a projection device to display the image.

(External Illuminated Image Display System) The reflector or image display sheet of the present invention is suitable for constituting an external illuminated image display system in combination with an external lighting device including a light source. In such a system, light from an external illuminator illuminated by a reflector (or a reflector included in an image display sheet) is reflected, and the reflected light is visually recognized in a controlled and as wide as possible observation angle range. It is possible and can be visually recognized even from a relatively long distance. Therefore, the image display system according to the present invention is particularly useful as a system for illuminating an image display such as a signboard installed on the roof of a building or a sign installed above a road.

For example, as a preferable mode for illuminating a signboard on a building roof, an example schematically shown in FIG. 18 can be given. In the illustrated example, an image display sheet including the reflector of the present invention is fixed to the surface of the signboard. The fixing of the sheet is performed using, for example, an adhesive. In the case of the signboard as shown in the figure, it is preferable to arrange the external lighting device so that the surface of the image display sheet is illuminated from above the signboard in the vertical direction. The direction of reflection of the light reflected on the surface of the image display sheet is vertically downward, and the observation angle range is as wide as possible for an observer on the ground (road, etc.) near the building. It is better to
In order to control the reflection direction in this way, for example, as shown in the example shown in FIG. 9 described above, the convex part of the reflector has a convex part precursor having a cut surface substantially perpendicular to the surface of the base layer precursor. It is preferably formed by using. In this case, the cut surface of the projection precursor is preferably arranged vertically upward.

As a preferred mode for illuminating a sign installed above a road, an example schematically shown in FIG. 19 can be given. In the illustrated example, an image display sheet including the reflector of the present invention is fixed to the surface of the substrate of the sign. The illuminating device is preferably installed on the side of a road (shoulder or the like) and projects light obliquely upward to the surface of the image display sheet. At this time, the light returning toward the lighting device should be reduced as much as possible because it is not visible to the vehicle driver traveling on the road. In order to control the reflection direction so that it can be visually recognized by a vehicle driver, a convex portion is formed using a convex precursor having a cut surface substantially perpendicular to the surface of the base layer precursor, as in the case of FIG. 18 described above. It is preferable to use a textured reflector. In the case of the illustrated example, the cut surface of the projection precursor is preferably arranged so as to face the lighting device side (the left side in the drawing) in the horizontal direction. As the external lighting device, a normal floodlight for signboard lighting or sign lighting can be used. Specific examples of such a floodlight include, for example, a floodlight “OPL-250” manufactured by Sumitomo 3M Limited,
A light projector disclosed in Japanese Patent No. 2910868 can be mentioned.

In the external illumination type image display system according to the present invention, the brightness and the contrast can be effectively improved as compared with a system using a white sheet colored with a white pigment. For example, when the image display body is installed outdoors at a position higher than the eye level of the observer, even on a cloudy day or dusk when a normal white sheet looks grayish,
In the image display sheet formed using the reflector of the present invention, the background portion looks bright white.

(Other Uses) The reflector of the present invention can also be used as a reflector for indirect illumination and as a projection screen. The reflector for indirect illumination does not directly irradiate the light of the light source to the illuminated object, but irradiates the light reflected by the reflector. Normally, in a reflector for indirect illumination, it is desirable to design the effective observation angle and the intensity distribution of reflected light in the observation range to a desired range. The reflector according to the present invention, particularly a reflector formed by a duplication method, is suitable as a reflector for indirect illumination because the shape and dimensions of the convex mirror and the concave mirror can be easily designed. How to use as a reflector for indirect lighting, for example, by placing a reflector on the ceiling in the room,
Light from the light source is irradiated from below, and the room is illuminated with the reflected light from the reflector. At this time, if the light source is made substantially invisible to an observer, illumination that gives a soft impression is possible. It is also possible to illuminate the room with light from a ceiling or a wall where a light source cannot be attached. Furthermore, even when the interior is to be illuminated with light from a place at a height or position that is hard to reach, such as a ceiling, the light source can be placed on the floor or in a place relatively close to the floor. Easy to replace. The indirect lighting as described above can also be used to illuminate a room in a special environment where a normal light source cannot be placed. As a special environment, for example,
This is an environment where the room is under high temperature, low temperature, high humidity, or underwater, or an environment in which explosion proof and dust proof are required. In such a case, the light source is placed outside the room, a reflector for indirect lighting is placed inside the room, the light of the light source is guided into the room to illuminate the reflector, and the room is illuminated with the reflected light from the reflector. In such a case, for example, part or all of the wall separating the room from the outside can be formed of a transparent plate (a glass plate or the like), and the light of the light source can be guided into the room through the transparent plate. Alternatively, a long light transmission body such as an optical fiber may be used to introduce light from a light source into the transmission body from one end in the length direction and emit light into the room from the other end in the length direction of the transmission body.

When used as a projection screen, a high-brightness observation angle is set in a relatively narrow range (for example, 1/3).
It is also possible to use a reflector whose maximum brightness observation angle is controlled to ± 30 degrees in the horizontal direction. In such a case, one each from the horizontal left direction and the right direction toward the screen
Different images can be respectively projected on the screen by two projectors. That is, two observers located horizontally and horizontally apart from each other with respect to the screen can display the image of one projector without disturbing the image of the other projector (the two images can be viewed in an overlapping manner). No) and can be recognized as a correct video. Such a projection system, for example,
Using the reflective screen according to the present invention as an information display plate,
It is suitable for providing projected images including different information to two observers approaching the information display board from left and right in the horizontal direction about the information display board.

[0078]

EXAMPLES (Examples 1 to 5) In this example, a reflector of the type shown in FIGS. 1 and 2 was manufactured. First, a coating material for a binding layer was applied to the surface of a support made of a polyester film using a bar coater. The coating thickness was set so that the thickness after drying would be 35 μm. The paint was 100 parts by mass of a polyvinyl butyral resin (“product number: B90” manufactured by Monsanto Company), and 23.3 parts by mass of an alkyd resin (“Aroplaz” (trademark) manufactured by Ashland Chemical). , A solvent (193 parts by mass of xylene and 310 parts by mass of n-butanol) and 40 parts by mass of a urea formaldehyde resin (trade name "Uformite F240" manufactured by Reichhold Chemicals) as a crosslinking agent. Next, before the coating for the bonding layer was dried, a plurality of glass beads having an average diameter of 74 μm ± 10 μm were uniformly spread on the surface of the coating.
Dry for 0 minutes. This buried the glass beads in the tie layer such that about 40-50% of their average diameter was in the tie layer.

Subsequently, a resin solution containing a polyurethane resin having a nonvolatile content of 25% by mass (manufactured by Sumitomo Bayer Urethane Co., Ltd.)
100 parts by mass of "Desmolac 4125" manufactured by Sumitomo Bayer Urethane Co., Ltd., and a polyisocyanate as a cross-linking agent "Trademark: Sumidur manufactured by Sumitomo Bayer Urethane Co., Ltd. ) N330
0 "} was added by a bar coater to a predetermined bar set (100 to 300 μm) for each case.
m) and dried to form a coating layer. This gives 1
A plurality of beads and a coating layer covering the exposed portion of the beads, a plurality of protrusions having a convex curved surface formed of the surface of the coating layer, and a plurality of depressions having a concave curved surface formed between adjacent convex portions. Was formed. Finally, aluminum was vacuum-deposited on the uneven surface formed by the above-mentioned projections and depressions, and a reflective film having a thickness of about 500 Å was adhered. Thereby, the first reflection film adhered to the convex curved surface,
The wide observation angle reflector of the present invention including the second reflection film adhered to the concave curved surface is completed.

(Example 6) A wide observation angle reflector of the present invention of this example was completed in the same manner as in the above example, except that the application of the resin liquid was performed with a bar set of 50 µm.

(Comparative Example 1) A wide observation angle reflector of this example was completed in the same manner as in the above example, except that the coating layer was not used. In this example, since no coating layer was used, no concave curved surface was formed between the adjacent convex portions. (Comparative Example 2) This example is an example in which a white reflective sheet (copy paper) having strong diffuse reflection is used as a reflector for comparison.

(Evaluation of Reflector) For the reflectors of each of the above examples (excluding Comparative Example 2), the concave mirror average depth (D: unit μ)
m) and the average distance between convex mirrors (P: unit μm) were measured using a laser microscope, and the ratio (D / P) was determined. The average depth of the concave mirror was determined at random by selecting a sample for measurement by cutting a substantially central portion of the reflector of each example into a 3 cm square.
The average distance defined above was measured for 0 micro concave mirrors and all micro convex mirrors (usually 3 or 4) surrounding the micro concave mirror. The average distance between the convex mirrors is determined by taking a laser microscope photograph of each of the above-mentioned materials, and measuring the distance between adjacent mirrors.
The average distance between the convex mirrors was measured on the photograph. The observation (measurement) conditions of the laser microscope were as follows. Laser microscope: Lasertec 1LM21 Objective lens: 50x Scan rate: Normal Gain: 12 o'clock direction Stage moving speed: 30-80 μm / 30sec Averaging processing: 9 × 9 Sample preprocessing: None

The reflection luminance of each example was measured as follows. The reflection luminance was measured by changing the measurement angle (observation angle) by irradiating white light from an angle of 0 degree with respect to the normal direction of the test piece surface so that the surface illuminance on the test piece surface became 150 lux. The measured value of luminance was obtained using a color luminance meter BM-5A (manufactured by Topcon Corporation). The unit is cd /
a m ^2. The distance between the test piece, the light source and the luminance meter was about 10 m. Table 1 shows the evaluation results of the reflectors in each example.
Shown in FIG. 5 shows graphs of Example 3 and Comparative Example 1 as examples of graphs obtained from the measurement results.

The effective observation angle is such that the absolute value of the luminance is 50 cd /
m is ² or more, the range of observation angles, including an observation angle of 0 degrees. Also, in the reflector of the present invention, the maximum luminance is usually obtained at 0 ° or a relatively low observation angle, but the observation angle range (1/3) at which 1/3 maximum luminance (a value of 1/3 of the maximum luminance) is obtained.
(3 maximum brightness observation angle) is also an effective parameter for evaluating the wide observation angle. For example, when the 1/3 maximum luminance observation angle is 10 degrees or less, the diffusivity is low. When the 1/3 maximum luminance observation angle exceeds 80 degrees, the diffusivity is increased, but the angle range in which the observation is bright cannot be widened.
When the 1/3 maximum luminance observation angle is in the range of 10 degrees or more and 80 degrees or less, preferably 75 degrees or less, the angle range in which the observation is bright can be widened. On the other hand, even if the 1/3 maximum luminance observation angle satisfies the above condition, if the effective observation angle is less than 50 degrees, it is difficult to observe brightly in a wide observation angle range. Therefore, when both of the observation angles defined as described above are in the range of 80 degrees or less, and the effective observation angle is 50 degrees or more, preferably 55 degrees or more, a particularly good wide observation angle is exhibited. It can be observed brightly over a wide observation angle range.

In order to control the direction of the effective reflected light within a predetermined observation angle range while maintaining the wide observation angle, both the effective observation angle of 50 degrees or more and the definition as described above are required. Are preferably 75 degrees or less, and preferably 70 degrees or less. For example, in the reflector of Example 6, the thickness of the coating layer is relatively thin, and the curvature of the concave surface formed on the surface of the coating layer applied between the adjacent convex portions is effective in a predetermined observation angle range. It was insufficient to control the direction of the reflected light. Therefore, although the wide observation angle can be evaluated to be higher than that of Comparative Example 1 (an example in which a micro concave mirror is not formed), the reflection directivity and the luminance were relatively lower than those of the other examples.

[0086]

[Table 1]

Example 7 A reflector according to this example was produced in the same manner as in Example 1 except that the above-described embossing method was used instead of the bead embedding method. In this example, a base layer with a convex portion was manufactured as follows. First, a base layer sheet made of a vinyl chloride resin was prepared, and embossing was performed thereon, thereby producing a base layer precursor having a structure shown in FIG. In the same manner as in Example 1, the surface of this base layer precursor was coated with a convex precursor, and a coating layer was formed so as to fill the space between the adjacent convex precursors. After forming the body, a reflecting film was formed to complete the reflecting body of this example. The bar set at the time of applying the resin liquid was 300 μm.

The height (height protruding from the surface of the base layer precursor) of the hemispherical convex precursor is 365 μm, and the diameter of the horizontal cross section of the convex precursor on the surface of the base layer precursor is 1 μm.
mm, the shortest distance between two adjacent convex precursors (the distance measured along the grid line) was 100 μm, and the curvature of the surface of the convex precursor was 530 μm. The roughness of the base layer precursor surface was measured with a laser microscope equipped with a three-dimensional surface roughness meter (manufactured by Lasertec Co., Ltd., product name: laser microscope) at a magnification of 200 times Rz (ten-point average roughness).
The value was 9.68 μm. The roughness of the reflector precursor surface was measured with a laser microscope described above at a magnification of 200.
Rz (ten-point average roughness) measured by a factor of 2,
It was 5.95 μm.

In the reflector of this example, a concave mirror was formed between four adjacent convex mirrors arranged in a grid pattern. The average depth D of the concave mirror is 55 μm, and 2
The average spacing P between the two convex mirrors is 675 μm,
D / P was 0.08.

The reflection characteristics of the reflector of this example were measured.
Was. The maximum luminance at an incident angle of 0 degree is 520 [cd /
m²], The maximum luminance at an incident angle of 20 degrees is 1,150.
[Cd / m ²]Met. In addition, incident angle 0 degree, reflection angle
(Observation angle) The luminance at 30 degrees is 230 [cd /
m²], Incident angle -20 degrees, reflection angle (observation angle) 50 degrees
Brightness is 450 [cd / m²], The effective observation angle is very
Showed that it was wide.

On the other hand, as a reference example, the reflection characteristics of a reflector having no concave mirror, in which a reflection film was formed by using a base layer precursor having no coating layer as it was, were similarly measured. As a result, the maximum luminance at an incident angle of 0 degree is 330 [c
d / m ² ] and the maximum luminance at an incident angle of 20 degrees is 560.
The luminance at [cd / m ² ], the incident angle of 0 degree, and the reflection angle of 30 degrees is 100 [cd / m ² ], and the luminance at the incident angle of −20 degrees and the reflection angle of 50 degrees is 120 [cd / m ² ]. Was. The measured values were lower than with a concave mirror, indicating a lower reflection directivity.

In the reference example, the overall luminance was lower than in the seventh embodiment. This is presumably because in the reference example in which the reflective film was formed directly on the positive irregularities of the base layer precursor transferred from the negative mold, the surface smoothness of the reflecting surface was lower than that in Example 7. However, it was found that when the coating layer was used, such a decrease in the reflection luminance could be effectively prevented. The measurement of the reflection luminance was performed by the same measuring method and conditions as in Example 1 described above. FIG. 20 schematically shows the measuring device. In the illustrated measuring device, the arrangement relationship between the light source and the luminance meter (incident angle and observation angle) is variable.

[0093]

As can be seen from the above description, according to the reflector of the present invention, it is extremely possible to control the direction of the effective reflected light within a predetermined observation angle range while maintaining a wide observation angle. It is easy, bright (ie, high brightness) and visible. Also,
The reflector according to the present invention is particularly useful as a component of an image display sheet used as a sign, a signboard, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one embodiment of a wide observation angle reflector of the present invention.

FIG. 2 is an enlarged cross-sectional view of one embodiment of the wide observation angle reflector of the present invention.

FIG. 3 is a schematic sectional view of another embodiment of the wide observation angle reflector of the present invention.

FIG. 4 is a cross-sectional view showing an example of a method for producing a wide observation angle reflector of the present invention.

FIG. 5 is a graph showing measurement results of reflection luminance obtained in Example 3 and Comparative Example 1.

FIG. 6 is a schematic cross-sectional view of one embodiment of the wide observation angle reflector of the present invention having a base layer precursor and a convex portion precursor.

FIG. 7 is a schematic cross-sectional view of another embodiment of the wide viewing angle reflector of the present invention having a base layer precursor and a convex precursor.

FIG. 8 is a schematic cross-sectional view of another embodiment of the wide observation angle reflector of the present invention having a base layer precursor and a projection precursor.

FIG. 9 is a schematic cross-sectional view of another embodiment of the wide viewing angle reflector of the present invention having a base layer precursor and a convex part precursor.

FIG. 10 is a schematic cross-sectional view of another embodiment of the wide viewing angle reflector of the present invention having a base layer precursor and a convex part precursor.

FIG. 11 is a schematic cross-sectional view of another embodiment of the wide viewing angle reflector of the present invention having a base layer precursor and a convex part precursor.

FIG. 12 is a schematic cross-sectional view of another embodiment of the wide observation angle reflector of the present invention having a base layer precursor and a convex portion precursor.

FIG. 13 is a schematic cross-sectional view of another embodiment of the wide observation angle reflector of the present invention having a base layer precursor and a convex part precursor.

FIG. 14 is a schematic cross-sectional view of another embodiment of the wide-viewing angle reflector of the present invention having a base layer precursor and a projection precursor.

FIG. 15 is a schematic plan view of another embodiment of the wide observation angle reflector of the present invention having a base layer precursor and a convex portion precursor.

FIG. 16 is a schematic plan view of still another embodiment of the wide observation angle reflector of the present invention having a base layer precursor and a projection precursor.

FIG. 17 is a schematic sectional view of still another embodiment of the wide-viewing-angle reflector of the present invention having a base layer precursor and a projection precursor.

FIG. 18 is a view showing a signboard installation mode using the wide observation angle reflector of the present invention.

FIG. 19 is a diagram showing an installation mode of a sign using the wide observation angle reflector of the present invention.

FIG. 20 is a schematic view of an apparatus used for measuring a reflection luminance in the example.

[Explanation of symbols]

1: support, 2: binding layer, 3: bead, 31: exposed portion, 32: buried portion, 33: space, 4: coating layer, 5: base layer, 6: convex portion, 60: reflective convex portion, 61: convex curved surface,
510: concave curved surface, 7: reflective film, 71: first reflective film, 7
2: Second reflective film. 53: base layer precursor, 54: convex part precursor, 101: reflector precursor.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D064 BA01 CA03 CA04 CA07 CA09 DA05 DA08 EB14 EB22 EB26 2H021 BA02 2H042 BA03 BA14 BA15 BA19 BA20 DA01 DA02 DA03 DA04 DA11 DA17 DA21 DB07 DB08 DC02 DE00 EA11 EA14 EA15 A17 A06 A17 BA03 CA02 CA12 CA26 CA32 CB01 CE04 CE20 CE22 EB05 FA02 FA03

Claims (5)

[Claims] A base layer having a front surface and a back surface; and a plurality of minute convex mirrors disposed adjacent to each other on the surface of the base layer and having a convex curved surface to which a first reflection film is in close contact. In the observation angle reflector, the base layer has a concave curved surface depressed from the surface of the base layer toward the back surface, and the concave curved surface is provided with a plurality of minute concave mirrors to which the second reflective film is in close contact. A wide observation angle reflector, wherein the minute concave mirror is disposed between the adjacent minute convex mirrors. 2. The surface roughness of an uneven reflection surface formed by connecting the first reflection film and the second reflection film to each other has an average distance between convex mirrors (P: unit μm) having an average depth of concave mirrors (D: unit μm). ) To the value (D / P) of 0.02
2. The wide viewing angle reflector of claim 1, wherein the reflector has a range of ~ 0.25. (A) a base layer having a front surface and a back surface; and (B) disposed adjacent to each other on the base layer surface, each being fixed to the base layer surface, and coming out of the base layer surface. A wide-viewing-angle reflector comprising: a plurality of convex portions having a convex curved surface bulging forward; and (C) a first reflective film in close contact with the convex curved surface of the convex portion. , A concave curved surface depressed from the surface of the base layer toward the rear surface is disposed, and the second reflective film is in close contact with the concave curved surface. 4. A base layer precursor having a plurality of protrusion precursors integrally bonded to a surface, and covering the protrusion precursors and filling a space between the protrusion precursors adjacent to each other. A coating layer disposed so as to have a predetermined thickness, wherein the base layer is composed of the base layer precursor and the coating layer, and the convex portion is the convex portion precursor and the same. The wide-observation-angle reflector according to claim 3, comprising a portion of the coating layer that covers, and the concave curved surface being a surface of the coating layer that fills a space between the convex precursors. 5. A bonding layer having a front surface and a back surface; and (b) a fixed portion adjacent to each other on the front surface of the bonding layer, partially embedded in the bonding layer, and a remaining portion. A wide observation angle reflector comprising: a plurality of beads exposed from the bonding layer; and (c) a first reflection film covering the beads. The wide observation angle reflector, which covers exposed portions of the beads and is adjacent to each other. An application layer having a predetermined thickness is arranged so as to fill a space between the exposed portions of the beads, and the application layer covering the exposed portions of the beads has a convex curved surface bulging in a direction from the bonding layer toward the application layer. Forming a convex portion, wherein the first reflective film is in close contact with the convex curved surface of the convex portion, and between the adjacent convex portions, from the surface of the coating layer depressed from the surface of the coating layer toward the bonding layer. A concave curved surface is disposed, and the concave curved surface has a (2) A wide-observation-angle reflector, wherein the reflection film is in close contact.