Resin molding
A resin molding is provided. The resin molding includes an optically transparent plate-shaped portion which consists essentially of a single material and which includes a first surface having a smooth surface portion, and a second surface having plural convex portions. Each of the plural convex portions includes a first inclined surface having a concavo-convex portion thereon; and a second inclined surface having a smooth surface portion. The concavo-convex portion allows at least part of light incident from the first surface to cause total reflection, diffraction and interference and to travel toward the smooth surface portion of the second inclined surface, and the smooth surface portion selectively reflects visible light in a predetermined wavelength range toward the first surface, so that when the first surface of the resin molding is observed from outside, the resin molding has a colored appearance with at least one color in addition to a metallic appearance.
1. A resin molding comprising:
an optically transparent plate-shaped portion consisting essentially of a single material,
wherein the plate-shaped portion includes:
a first surface having a smooth surface portion, and
a second surface having plural convex portions thereon,
wherein each of the plural convex portions includes:
a first inclined surface having a concavo-convex portion thereon, the concavo-convex portion comprising a total reflection portion which is arranged with a predetermined pitch; and
a second inclined surface having a smooth surface portion,
wherein a part of a light incident from the first surface is totally reflected, by the total reflection portion of the concavo-convex portion of the first inclined surface, toward the smooth surface portion of the second inclined surface and then totally reflected by the smooth surface portion of the second inclined surface while the predetermined pitch causes diffraction and interference of another part of the light incident from the first surface, and the smooth surface portion of the second inclined surface selectively reflects visible light in a predetermined wavelength range toward the first surface, so that when the first surface of the resin molding is observed from outside, the resin molding has a colored appearance with at least one color in addition to a metallic appearance.
2. The resin molding according to claim 1 , wherein the concavo-convex portion includes a diffraction grating having a saw blade shape.
3. The resin molding according to claim 1 , wherein the plural convex portions include at least one convex portion having a property such that the concavo-convex portion of the first inclined surface thereof is different from the concavo-convex portion of the first inclined surfaces of the other convex portions in at least one of properties selected from diffraction plane angle, total reflection plane angle and groove angle.
4. The resin molding according to claim 1 , wherein at least one of the first surface and the second surface is a curved surface.
5. The resin molding according to claim 1 , wherein the first inclined surface includes a smooth transparent portion having a shape of pattern selected from characters, figures and signs so that the transparent portion displays an image of the pattern when the first surface of the resin molding is observed from outside, or a portion of the first inclined surface having the concavo-convex portion has a shape of pattern selected from characters, figures and signs so that the portion displays an image of the pattern when the first surface of the resin molding is observed from outside.
6. The resin molding according to claim 1 , wherein the second inclined surface consists of the smooth surface portion.
7. The resin molding according to claim 1 , wherein at least one of the plural convex portions has a shape similar to triangular shape in which a top thereof is sharp or a shape similar to trapezoid in which a top thereof is flat, the first inclined surface is one side of the shape similar to triangular shape or the shape similar to trapezoid, and the second inclined surface is another one side of the shape similar to triangular shape or the shape similar to trapezoid.