Decoration panel

A large number of small reflection portions are continuously formed over a back face of a base member opposite the light impinging side, in an arbitrary arrangement. The small reflection portions are each formed to have a boundary surface for reflection, interference, and diffraction of incident light impinging onto the base member, to thereby produce random changes in the brightness of reflection light over the entirety of the decoration panel. A reflection layer is formed on the boundary surfaces of the small reflection portions such that the boundary surfaces function as mirror surfaces and reflect light propagating through the base member toward the front face of the base member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a decoration panel used for molded plastic products for vehicles, furniture, cellular phones, etc.

2. Description of the Related Art

A known example of a conventional decoration panel is a garnish (decoration panel for automobiles) which is attached to a rear end of a passenger car to be located between rear combination lamps (see Japanese Patent Application Laid-Open (kokai) No. H04-78632).

A decoration panel of such a type includes a cover formed of a transparent synthetic resin material such as acrylic, and a mount base member for mounting the cover to the body of an automobile. The cover has a smooth outer surface and an inner surface that faces the mount base member and is embossed. Fish-eye portions each having a concave hemispherical shape are continuously formed on the surface of the mount base member facing the inner surface of the cover, and silver metallic paint is applied to the fish-eye portions to thereby form a metallic coated surface.

In such a decoration panel, light having passed through the cover is complicatedly scattered by means of the embossed inner surface of the cover. When the scattered light reaches the metallic coated surface of the mount base member, by means of the action of concave mirrors (the fish-eye-portions each having a concave hemispherical shape), reflection light is produced, while disturbance in reflection of the incident light is mitigated, whereby a Fresnel lens effect is attained. Thus, a decoration panel which gives a sense of depth can be provided.

Such a conventional decoration panel is composed of an embossed cover, and a mount base member which has concave, hemispherical fish-eye portions formed on a surface facing the cover, with a metallic coated surface formed through applying a silver metallic paint to the fish-eye portions. Therefore, such a conventional decoration panel is suitable for use as garnishes for passenger cars. However, they are not suitable for molded plastic products for furniture or cellular phones, for the following reasons. Since the conventional decoration panel has a structure in which the cover and the mount base member are disposed to face each other with a space therebetween, the decoration panel has a large thickness and the thickness cannot be decreased. In addition, the large number of components of the decoration panel increases cost.

Moreover, the metallic coated surface of the mount base member of the conventional decoration panel is composed of concave mirrors, which collect and reflect the light scattered by the embossed inner surface of the cover to thereby produce spots of light having a diameter corresponding to the size of the concave mirrors. Therefore, spots of reflection light generally of the same brightness. In addition, even when the viewing point is changed in relation to the decoration panel, the brightness of light spots does not change. As a result, the conventional decoration panel has problems of failing to provide variation and not being attractive when used for decoration of an automobile interior part such as an instrument panel or door trim.

SUMMARY OF THE INVENTION

The present invention has been achieved so as to solve the above-described problems in conventional decoration panels, and an object of the present invention is to provide a decoration panel which provides light decoration which is full of variation and is attractive, and which visually influences a viewer to thereby soothe, relax, and comfort the viewer.

In order to achieve the above-described object, the present invention provides a decoration panel comprising a transparent plate-shaped base member having a large number of small reflection portions continuously formed in an arbitrary arrangement over a rear face of the base member opposite a front face thereof, on which light impinges, the small reflection portions each having a boundary surface capable of causing reflection, interference, and diffraction of incident light impinging onto the base member to thereby generate random changes in brightness of reflection light from the boundary surface; and a reflection layer formed on the boundary surfaces of the small reflection portions such that the boundary surfaces function as mirror surfaces and reflect light propagating through the base member toward the front face of the base member, wherein upon a change in at least one of the direction of the incident light in relation to the base member, a viewing point in relation to the base member, and the position of the base member in relation to the incident light or the viewing point, irregular changes occur in the brightness of reflection light generated through reflection, interference, and diffraction of light occurring at the small reflection portions, and chromatic aberrations are produced through shift of light wavelengths.

In the decoration panel according to the present invention, through a change in at least one of the direction of the incident light in relation to the base member, a viewing point in relation to the base member, and the position of the base member, an irregularly changing light-dark pattern is produced in the brightness of reflection light generated by the small reflection portions and the reflection layer, which light-dark pattern resembles that of sunlight passing through trees. Thus, attractive light decoration which is full of changes can be provided.

Preferably, the large number of small reflection portions have three-dimensional concave boundary surfaces which have shapes determined through addition of a 1/f fluctuation to a basic shape and which are continuous along the back face of the base member. Preferably, the basic shape of the small reflection portions is a three-dimensional shape selected from a triangular three-dimensional shape, a trapezoidal three-dimensional shape, a hemispherical three-dimensional shape, a hemi-elliptical-spherical three-dimensional shape, and a wavy three-dimensional shape, wherein the three-dimensional shape is continuously, randomly, and two-dimensionally formed at an arbitrary pitch over the rear face of the base member.

Since the small reflection portions have three-dimensional concave boundary surfaces continuously formed along the back face of the base member through impartment of a 1/f fluctuation to the basic shape, a viewer can see an irregularly changing light-dark pattern in the brightness of reflection light from the small reflection portions and the reflection layer, which light-dark pattern resembles that of sunlight passing through trees. Thus, the decoration panel of the present embodiment can exhibit a light decoration effect which soothes, relaxes, and/or comforts the viewer.

Preferably, a semi-transparent or transparent decoration layer having a decoration pattern is formed on the front face of the base member. In this case, reflection light generated by the small reflection portions and the reflection layer can impart a randomly changing light-dark pattern to the decoration pattern of the decoration layer, so that the appearance of the decoration pattern can be improved.

Preferably, a single-layer or multi-layer optical thin film is provided at a boundary between the small reflection portions and the reflection layer. In this case, the decoration panel can have a colored light decoration effect which soothes, relaxes, and/or comforts the viewer more effectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

A decoration panel according to a first embodiment of the present invention will now be described with reference toFIGS. 1 to 3. Notably, the present invention is not limited to the embodiment described below.

FIG. 1is a perspective view of the decoration panel according to the first embodiment;FIG. 2is an enlarged cross-sectional view taken along line2-2ofFIG. 1; andFIG. 3is an enlarged cross-sectional view taken along line3-3ofFIG. 1.

As shown inFIG. 1, the decoration panel according to the first embodiment, which is denoted by reference numeral10, includes a plate-shaped base member11which has a predetermined thickness and which is formed of a transparent synthetic resin such as acrylic resin or polycarbonate or a transparent material such as glass. A front face11aof the base member11on which light impinges is a flat surface. A large number of small reflection portions12are continuously formed over the entire region of a back face11bof the base member11, opposite the front face11a, in an arbitrary arrangement. The small reflection portions12are each formed to have a boundary surface for reflection (total reflection, perfect or imperfect diffusion reflection, transmission diffusion), interference, and diffraction of incident light13impinging onto the base member11, to thereby produce random changes in the brightness of reflection light over the entirety of the decoration panel10.

Notably, the incident light13impinging onto the decoration panel10may be light from any of various illumination lamps or natural light such as sunlight.

Next, a specific method of providing irregular changes in the brightness of reflection light produced by the small reflection portions12will be described with reference toFIGS. 1 and 3.

As shown inFIG. 1, the small reflection portions12have a triangular-roof-like basic shape, and a 1/f fluctuation is imparted to the basic shape, whereby concave boundary surfaces12aeach assuming a triangular-roof-like three-dimensional shape are continuously formed along the back face of the base member as shown inFIGS. 2 and 3. The concave boundary surfaces12aprovide an irregularly changing light-dark pattern in the brightness of reflection light, which pattern resembles that of sunlight through trees. The shape of the concave boundary surfaces12ais determined by the following 1/f fluctuation function f(x).

That is, each of the concave boundary surfaces12aassumes a shape determined by a curve which is obtained by superposing a plurality of sinusoidal curves having different frequencies (2ix) while scaling them with proper coefficients 2−i(amplitude). The graph ofFIG. 4shows a curve411determined as described above. Reference numeral412denotes the plurality of sinusoidal curves having different frequencies.

As shown inFIGS. 1 to 3, the small reflection portions12are continuously arranged in row and column directions at predetermined equal intervals L (0<L<10 mm). The small reflection portions12in a certain row are shifted in the column direction from those in a row adjacent thereto by an amount corresponding to a single interval L.

Further, each concave boundary surface12ahas a depth h in a range of 0 to 20 mm, inclusive. Further, in the case where the base member is formed of polycarbonate, each concave boundary surface12ahas a reflection angle θ1of about 40 degrees, and an inclination angle θ2in a range of 0 to 90°, inclusive.

Further, as shown inFIGS. 2 and 3, a reflection layer15is formed on the concave boundary surfaces12aof the small reflection portions12such that the concave boundary surfaces12afunction as mirror surfaces and reflect light propagating through the base member11toward the front face of the base member11. This reflection layer15is formed through vapor deposition of aluminum or any other metal for formation of mirror surfaces.

The decoration panel10according to the first embodiment operates as follows. As shown inFIGS. 1 to 3, when the front face11aof the base member11is irradiated with the incident light13, the incident light13propagates within the base member11as refraction light, and reaches the small reflection portions12. The refraction light having reached the small reflection portions12is reflected, subjected to interference, and diffracted in accordance with the shapes of the small reflection portions12determined by the 1/f fluctuation function f(x). Thus, an irregularly changing light-dark pattern is imparted to the brightness of reflection light propagating toward the front face11aof the base member11, and chromatic aberrations are produced by means of shift of light wavelength. Moreover, of the above-described refracted light, light propagating through the base member11and reflected by the reflection layer15is caused to return to the interior of the base member11, and contributes to generation of an irregularly changing light-dark pattern. Further, in this case, a portion of reflection light propagating from the small reflection portions12and the reflection layer15interferes with a portion of the incident light13reflected by the front face11aof the base member11, whereby light beams of some colors become strong, and light beams of the remaining colors are weakened, whereby a colored light pattern can be generated.

Accordingly, in the first embodiment, when at least one of the direction of the incident light13in relation to the base member11, the viewing point14of a viewer in relation to the front face11aof the base member11, and the position of the base member11in relation to the viewing point14or the incident light13is changed, the refection layer15and the small reflection portions12having a 1/f fluctuation generate an irregularly changing light-dark pattern of reflection brightness, which resembles sunlight through trees. The decoration panel10of the present embodiment may be attached to automobile interior parts such as an instrument panel or door trim, in such a manner that decoration panel10is viewed from the light incident side. Thus, attractive light decoration which is full of changes can be provided to the automobile interior parts.

Further, through impartment of a 1/f fluctuation to the three-dimensional concave boundary surfaces12a, the brightness of reflection light generated by the concave boundary surfaces12aand the reflection layer15changes irregularly, so that the light-dark pattern of the brightness causes a viewer to feel as if he or she were under sunlight passing through trees. Thus, the decoration panel of the present embodiment can exhibit a light decoration effect which soothes, relaxes, and/or comforts the viewer.

Second Embodiment

Next, a decoration panel according to a second embodiment of the present invention will now be described with reference toFIGS. 5 to 7.

FIG. 5is a perspective view of the decoration panel according to the second embodiment;FIG. 6is an enlarged cross-sectional view taken along line6-6ofFIG. 5; and FIG.7is an enlarged cross-sectional view taken along line7-7ofFIG. 5.

As shown inFIG. 5, the decoration panel according to the second embodiment, which is denoted by reference numeral20, includes a plate-shaped base member21which has a predetermined thickness and which is formed of a transparent synthetic resin such as acrylic resin or polycarbonate or a transparent material such as glass. A front face21aof the base member21on which light impinges is a flat surface. A large number of small reflection portions22are continuously formed over the entire region of a back face21bof the base member21, opposite the front face21a, in an arbitrary arrangement. The small reflection portions22are each formed to have a boundary surface for reflection (total reflection, perfect or imperfect diffusion reflection, transmission diffusion), interference, and diffraction of incident light23impinging onto the base member21, to thereby produce random changes in the brightness of reflection light over the entirety of the decoration panel20.

Notably, the incident light23impinging onto the decoration panel20may be light from any of various illumination lamps or natural light such as sunlight.

Next, a specific method of providing irregular changes in the brightness of reflection light produced by the small reflection portions22will be described with reference toFIGS. 5 to 7.

As shown inFIG. 5, the small reflection portions22have a trapezoidal-roof-like basic shape, and a 1/f fluctuation is imparted to the basic shape, whereby concave boundary surfaces22aeach assuming a trapezoidal-roof-like three-dimensional shape are continuously formed along the back face of the base member, as shown inFIGS. 6 and 7. The concave boundary surfaces22aprovide an irregularly changing light-dark pattern in the brightness of reflection light, which pattern resembles that of sunlight through trees. The shape of the concave boundary surfaces22ais determined by the 1/f fluctuation function f(x) shown in the above-described Eq. 1.

That is, each of the concave boundary surfaces22aassumes a shape determined by a curve which is obtained by superposing a plurality of sinusoidal curves having different frequencies (2ix) while scaling them with proper coefficients 2−i(amplitude).

As shown inFIGS. 5 to 7, the small reflection portions22are continuously arranged in row and column directions at predetermined equal intervals L (0<L<10 mm). The small reflection portions22in a certain row are shifted in the column direction from those in a row adjacent thereto by an amount corresponding to a single interval L.

Further, each concave boundary surface22ahas a depth h in a range of 0 to 20 mm, inclusive. Further, in the case where the base member is formed of polycarbonate, each concave boundary surface22ahas a reflection angle θ1of about 40 degrees, and an inclination angle θ2in a range of 0 to 90°, inclusive.

Further, as shown inFIGS. 6 and 7, a reflection layer25is formed on the concave boundary surfaces22aof the small reflection portions22such that the concave boundary surfaces22afunction as mirror surfaces and reflect light propagating through the base member21toward the front face of the base member21. This reflection layer25is formed through vapor deposition of aluminum or any other metal for formation of mirror surfaces.

The decoration panel20according to the second embodiment operates as follows. As shown inFIGS. 5 to 7, when the front face21aof the base member21is irradiated with the incident light23, the incident light23propagates within the base member21as refraction light, and reaches the small reflection portions22. The refraction light having reached the small reflection portions22is reflected, subjected to interference, and diffracted in accordance with the shapes of the small reflection portions22determined by the 1/f fluctuation function f(x). Thus, an irregularly changing light-dark pattern is imparted to the brightness of reflection light propagating toward the front face21aof the base member21, and chromatic aberrations are produced by means of shift of light wavelength. Moreover, of the above-described refracted light, light propagating through the base member21and reflected by the reflection layer25is caused to return to the interior of the base member21, and contributes to generation of an irregularly changing light-dark pattern. Further, in this case, a portion of reflection light propagating from the small reflection portions22and the reflection layer25interferes with a portion of the incident light23reflected by the front face21aof the base member21, whereby light beams of some colors become strong, and light beams of the remaining colors are weakened, whereby a colored light pattern can be generated.

Accordingly, in the second embodiment, when at least one of the direction of the incident light23in relation to the base member21, the viewing point24of a viewer in relation to the front face21aof the base member21, and the position of the base member21in relation to the viewing point24or the incident light23is changed, the reflection layer25and the small reflection portions22having a 1/f fluctuation generate an irregularly changing light-dark pattern of reflection brightness, which resembles sunlight through trees. The decoration panel20of the present embodiment may be attached to automobile interior parts such as an instrument panel or door trim, in such a manner that decoration panel20is viewed from the light incident side. Thus, attractive light decoration which is full of changes can be provided to the automobile interior parts.

Further, through impartment of a 1/f fluctuation to the three-dimensional concave boundary surfaces22a, the brightness of reflection light generated by the concave boundary surfaces22aand the reflection layer25changes irregularly, so that the light-dark pattern of the brightness causes a viewer to feel as if he or she were under sunlight passing through trees. Thus, the decoration panel of the present embodiment can exhibit a light decoration effect which soothes, relaxes, and/or comforts the viewer.

Third Embodiment

Next, a decoration panel according to a third embodiment of the present invention will now be described with reference toFIGS. 8 to 10.

FIG. 8is a perspective view of the decoration panel according to the third embodiment;FIG. 9is an enlarged cross-sectional view taken along line9-9ofFIG. 8; andFIG. 10is an enlarged cross-sectional view taken along line10-10ofFIG. 8.

As shown inFIG. 8, the decoration panel according to the third embodiment, which is denoted by reference numeral30, includes a plate-shaped base member31which has a predetermined thickness and which is formed of a transparent synthetic resin such as acrylic resin or polycarbonate or a transparent material such as glass. A front face31aof the base member31on which light impinges is a flat surface. A large number of small reflection portions32are continuously formed over the entire region of a back face31bof the base member31, opposite the front face31a, in an arbitrary arrangement. The small reflection portions32are each formed to have a boundary surface for reflection (total reflection, perfect or imperfect diffusion reflection, transmission diffusion), interference, and diffraction of incident light33impinging onto the base member31, to thereby produce random changes in the brightness of reflection light over the entirety of the decoration panel30.

Notably, the incident light33impinging onto the decoration panel30may be light from any of various illumination lamps or natural light such as sunlight.

Next, a specific method of providing irregular changes in the brightness of reflection light produced by the small reflection portions32will be described with reference toFIGS. 8 to 10.

As shown inFIG. 8, the small reflection portions32have a hemispherical-roof-like basic shape, and a 1/f fluctuation is imparted to the basic shape, whereby concave boundary surfaces32aeach assuming a hemispherical-roof-like three-dimensional shape are continuously formed along the back face of the base member, as shown inFIGS. 9 and 10. The concave boundary surfaces32aprovide an irregularly changing light-dark pattern in the brightness of reflection light, which pattern resembles that of sunlight through trees. The shape of the concave boundary surfaces32ais determined by the 1/f fluctuation function f(x) shown in the above-described Eq. 1.

That is, each of the concave boundary surfaces32aassumes a shape determined by a curve which is obtained by superposing a plurality of sinusoidal curves having different frequencies (2ix) while scaling them with proper coefficients 2−i(amplitude).

As shown inFIGS. 8 to 10, the small reflection portions32are continuously arranged in row and column directions at predetermined equal intervals L (0<L<10 mm). The small reflection portions32in a certain row are shifted in the column direction from those in a row adjacent thereto by an amount corresponding to a single interval L.

Further, each concave boundary surface32ahas a depth h in a range of 0 to 20 mm, inclusive. Further, in the case where the base member is formed of polycarbonate, each concave boundary surface32ahas a reflection angle θ1of about 40 degrees, and an inclination angle θ2in a range of 0 to 90°, inclusive.

Further, as shown inFIGS. 9 and 10, a reflection layer35is formed on the concave boundary surfaces32aof the small reflection portions32such that the concave boundary surfaces32afunction as mirror surfaces and reflect light propagating through the base member31toward the front face of the base member31. This reflection layer35is formed through vapor deposition of aluminum or any other metal for formation of mirror surfaces.

The decoration panel30according to the third embodiment operates as follows. As shown inFIGS. 8 to 10, when the front face31aof the base member31is irradiated with the incident light33, the incident light33propagates within the base member31as refraction light, and reaches the small reflection portions32. The refraction light having reached the small reflection portions32is reflected, subjected to interference, and diffracted in accordance with the shapes of the small reflection portions32determined by the 1/f fluctuation function f(x). Thus, an irregularly changing light-dark pattern is imparted to the brightness of reflection light propagating toward the front face31aof the base member31, and chromatic aberrations are produced by means of shift of light wavelength. Moreover, of the above-described refracted light, light propagating through the base member31and reflected by the reflection layer35is caused to return to the interior of the base member31, and contributes to generation of an irregularly changing light-dark pattern. Further, in this case, a portion of reflection light propagating from the small reflection portions32and the reflection layer35interferes with a portion of the incident light33reflected by the front face31aof the base member31, whereby light beams of some colors become strong, and light beams of the remaining colors are weakened, whereby a colored light pattern can be generated.

Accordingly, in the third embodiment, when at least one of the direction of the incident light33in relation to the base member31, the viewing point34of a viewer in relation to the front face31aof the base member31, and the position of the base member31in relation to the viewing point34or the incident light33is changed, the reflection layer35and the small reflection portions32having a 1/f fluctuation generate an irregularly changing light-dark pattern of reflection brightness, which resembles sunlight through trees. The decoration panel30of the present embodiment may be attached to automobile interior parts such as an instrument panel or door trim, in such a manner that decoration panel30is viewed from the light incident side. Thus, attractive light decoration which is full of changes can be provided to the automobile interior parts.

Further, through impartment of a 1/f fluctuation to the three-dimensional concave boundary surfaces32a, the brightness of reflection light generated by the concave boundary surfaces32aand the reflection layer35changes irregularly, so that the light-dark pattern of the brightness causes a viewer to feel as if he or she were under sunlight passing through trees. Thus, the decoration panel of the present embodiment can exhibit a light decoration effect which soothes, relaxes, and/or comforts the viewer.

Fourth Embodiment

Next, a decoration panel according to a fourth embodiment of the present invention will now be described with reference toFIGS. 11 to 13.

FIG. 11is a perspective view of the decoration panel according to the fourth embodiment;FIG. 12is an enlarged cross-sectional view taken along line12-12ofFIG. 11; andFIG. 13is an enlarged cross-sectional view taken along line13-13ofFIG. 11.

As shown inFIG. 11, the decoration panel according to the fourth embodiment, which is denoted by reference numeral40, includes a plate-shaped base member41which has a predetermined thickness and which is formed of a transparent synthetic resin such as acrylic resin or polycarbonate or a transparent material such as glass. A front face41aof the base member41on which light impinges is a flat surface. A large number of small reflection portions42are continuously formed over the entire region of a back face41bof the base member41, opposite the front face41a, in an arbitrary arrangement. The small reflection portions42are each formed to have a boundary surface for reflection (total reflection, perfect or imperfect diffusion reflection, transmission diffusion), interference, and diffraction of incident light43impinging onto the base member41, to thereby produce random changes in the brightness of reflection light over the entirety of the decoration panel40.

Notably, the incident light43impinging onto the decoration panel40may be light from any of various illumination lamps or natural light such as sunlight.

Next, a specific method of providing irregular changes in the brightness of reflection light produced by the small reflection portions42will be described with reference toFIGS. 11 to 13.

As shown inFIG. 11, the small reflection portions42have a hemi-elliptical-spherical-roof-like basic shape, and a 1/f fluctuation is imparted to the basic shape, whereby concave boundary surfaces42aeach assuming a hemi-elliptical-spherical-roof-like three-dimensional shape are continuously formed along the back face of the base member, as shown inFIGS. 12 and 13. The concave boundary surfaces42aprovide an irregularly changing light-dark pattern in the brightness of reflection light, which pattern resembles that of sunlight through trees. The shape of the concave boundary surfaces42ais determined by the 1/f fluctuation function f(x) shown in the above-described Eq. 1.

That is, each of the concave boundary surfaces42aassumes a shape determined by a curve which is obtained by superposing a plurality of sinusoidal curves having different frequencies (2ix) while scaling them with proper coefficients 2−i(amplitude).

As shown inFIGS. 11 to 13, the small reflection portions42are continuously arranged in row and column directions at predetermined equal intervals L (0<L<10 mm). The small reflection portions42in a certain row are shifted in the column direction from those in a row adjacent thereto by an amount corresponding to a single interval L.

Further, each concave boundary surface42ahas a depth in a range of 0 to 20 mm, inclusive. Further, in the case where the base member is formed of polycarbonate, each concave boundary surface42ahas a reflection angle θ1of about 40 degrees, and an inclination angle θ2in a range of 0 to 90°, inclusive.

Further, as shown inFIGS. 12 and 13, a reflection layer45is formed on the concave boundary surfaces42aof the small reflection portions42such that the concave boundary surfaces42afunction as mirror surfaces and reflect light propagating through the base member41toward the front face of the base member41. This reflection layer45is formed through vapor deposition of aluminum or any other metal for formation of mirror surfaces.

The decoration panel40according to the fourth embodiment operates as follows. As shown inFIGS. 11 to 13, when the front face41aof the base member41is irradiated with the incident light43, the incident light43propagates within the base member41as refraction light, and reaches the small reflection portions42. The refraction light having reached the small reflection portions42is reflected, subjected to interference, and diffracted in accordance with the shapes of the small reflection portions42determined by the 1/f fluctuation function f(x). Thus, an irregularly changing light-dark pattern is imparted to the brightness of reflection light propagating toward the front face41aof the base member41, and chromatic aberrations are produced by means of shift of light wavelength. Moreover, of the above-described refracted light, light propagating through the base member41and reflected by the reflection layer45is caused to return to the interior of the base member41, and contributes to generation of an irregularly changing light-dark pattern. Further, in this case, a portion of reflection light propagating from the small reflection portions42and the reflection layer45interferes with a portion of the incident light43reflected by the front face41aof the base member41, whereby light beams of some colors become strong, and light beams of the remaining colors are weakened, whereby a colored light pattern can be generated.

Accordingly, in the fourth embodiment, when at least one of the direction of the incident light43in relation to the base member41, the viewing point44of a viewer in relation to the front face41aof the base member41, and the position of the base member41in relation to the viewing point44or the incident light43is changed, the reflection layer45and the small reflection portions42having a 1/f fluctuation generate an irregularly changing light-dark pattern of reflection brightness, which resembles sunlight through trees. The decoration panel40of the present embodiment may be attached to automobile interior parts such as an instrument panel or door trim, in such a manner that decoration panel40is viewed from the light incident side. Thus, attractive light decoration which is full of changes can be provided to the automobile interior parts.

Further, through impartment of a 1/f fluctuation to the three-dimensional concave boundary surfaces42a, the brightness of reflection light generated by the concave boundary surfaces42aand the reflection layer45changes irregularly, so that the light-dark pattern of the brightness causes a viewer to feel as if he or she were under sunlight passing through trees. Thus, the decoration panel of the present embodiment can exhibit a light decoration effect which soothes, relaxes, and/or comforts the viewer.

Fifth Embodiment

Next, a decoration panel according to a fifth embodiment of the present invention will now be described with reference toFIGS. 14 and 15.

FIG. 14is an enlarged cross-sectional view of a main portion of a decoration panel according to the fifth embodiment of the present invention; andFIG. 15is another enlarged cross-sectional view of a main portion of the decoration panel according to the fifth embodiment.

This fifth embodiment shows a modification of the small reflection portions12of the decoration panel10according to the first embodiment. As in the case shown inFIGS. 2 and 3, the small reflection portions12have a triangular-roof-like basic shape, and a 1/f fluctuation is imparted to the basic shape, whereby concave boundary surfaces12aeach assuming a triangular-roof-like three-dimensional shape are continuously formed along the back face of the base member. Further, a reflection layer15is formed on the concave boundary surfaces12a, and a semi-transparent or transparent decoration layer18, which has a decoration pattern such a grain pattern, a floral pattern, or a geometric pattern, is formed on the front face11aof the base member11, onto which light impinges.

In the decoration panel according to the fifth embodiment, since the decoration layer18having a decoration pattern is formed on the front face11aof the base member11, onto which light impinges, reflection light generated by the small reflection portions12and the reflection layer15can impart a randomly changing light-dark pattern to the decoration pattern of the decoration layer18, so that the appearance of the decoration pattern can be improved.

Sixth Embodiment

Next, a decoration panel according to a sixth embodiment of the present invention will now be described with reference toFIG. 16.

FIG. 16is an enlarged cross-sectional view of a main portion of a decoration panel according to the sixth embodiment of the present invention.

As shown inFIG. 16, the decoration panel10of the sixth embodiment includes a single-layer or multi-layer optical thin film17provided at a boundary between the concave boundary surfaces12aand the reflection layer15formed on the concave boundary surfaces12aof the small reflection portions12of the decoration panel10.

The decoration panel10according to the sixth embodiment can provide action and effects similar to those of the above-described first through fourth embodiments. In addition, since the single-layer or multi-layer optical thin film17is provided at the boundary between the concave boundary surfaces12aand the reflection layer15, the decoration panel10can have a colored light decoration effect which soothes, relaxes, and/or comforts the viewer more effectively.

Notably, the basic shape of the small reflection portions of the decoration panel of the present invention is not limited to the triangular-roof-like shape, the trapezoidal-roof-like shape, the hemispherical-roof-like shape, and the hemi-elliptical-spherical-roof-like shape, which are shown in the above-described embodiments. The small reflection portions may have any basic shape insofar as the selected basic shape can generate irregular changes in the brightness of reflection light from the small reflection portions.

Further, the three-dimensional concave boundary surfaces formed by the small reflection portions of the decoration panel of the present invention are not limited to those having shapes determined by the 1/f fluctuation function shown in Eq. 1. The shapes of the concave boundary surfaces may be determined by making use of a table of random numbers.

Furthermore, in the above-described embodiments, the small reflection portions of the decoration panel of the present invention are formed on the back face of the base member. However, the present invention is not limited thereto. The small reflection portions may be formed on the front face of the base member on the light incidence side. Further, the front face of the base member on the light incidence side is not necessarily required to be a smooth surface, and may assume a curved shape such as a wavy shape.

In the fifth embodiment, the reflection layer15is formed on the concave boundary surfaces12aof the small reflection portions12of the decoration panel10according to the first embodiment. However, the present invention is not limited thereto. The reflection layer may be formed on the concave boundary surfaces of the small reflection portions shown in the second to fourth embodiments. In this case as well, the action and effects similar to those attained in the fifth embodiment can be attained. Further, the single-layer or multi-layer optical thin film of the sixth embodiment may be applied to the reflection layers of the small reflection portions shown in the second to fourth embodiments.