Method for manufacturing anodized alumina, and device and method for inspecting the same

1. A method of manufacturing an article having anodized alumina on a surface thereof, comprising: irradiating a surface of the article having anodized alumina with a structure having two or more pores in which a pore interval is less than or equal to a wavelength of visible light on the surface thereof and reflecting colored light, with light from an illumination device after the anodized alumina is formed; capturing an image of reflected colored light from the surface of the article having anodized alumina on the surface using an imaging device; acquiring color information from an image captured by the imaging device; and inspecting a shape of the pore of the article having anodized alumina on the surface based on the color information, wherein in the capturing the image of the reflected colored light from the surface of the article having anodized alumina on the surface using the imaging device, the imaging device having an optical axis at an angle of 45 to 89.9 degrees with respect to a normal line of the surface of anodized alumina.

2. The method of manufacturing an article having anodized alumina on the surface thereof according to claim 1 , wherein in the capturing the image of the reflected light from the surface of the article having anodized alumina on the surface using the imaging device, the angle of the optical axis of the imaging device is 65 to 89.9 degrees with respect to the normal line of the surface of anodized alumina.

3. The method of manufacturing an article having anodized alumina on a surface thereof according to claim 1 , wherein in the capturing the image of the reflected light from the surface of the article having anodized alumina on the surface using the imaging device, an angle of an optical axis of the imaging device is 80 to 89.9 degrees with respect to a normal line of the surface of anodized alumina.

4. The method of manufacturing an article having anodized alumina on a surface thereof according to claim 1 , further comprising inspecting a mold release agent attached to a fine concave-convex structure on the surface of the article based on the color information.

5. The method of manufacturing an article having anodized alumina on a surface thereof according to claim 1 , further comprising inspecting a flow pattern of the article having anodized alumina on the surface based on the color information.

6. The method of manufacturing an article having anodized alumina on a surface thereof according to claim 1 , wherein the inspecting the shape of the pore of the article having anodized alumina on the surface based on the color information comprises

capturing an image of reflected light from the surface of the article having anodized alumina on the surface as an RGB signal, and

inspecting a shape of the pore of the article having anodized alumina on the surface based on information of the RGB signal.

7. The method of inspecting an anodized alumina according to claim 6 , wherein in the capturing the image of the reflected light from the surface of the anodized alumina using the imaging device, the angle of the optical axis of the imaging device is 65 to 89.9 degrees with respect to the normal line of the surface of anodized alumina.

8. The method of inspecting an anodized alumina according to claim 6 , wherein in the capturing the image of the reflected light from the surface of the anodized alumina using the imaging device, an angle of an optical axis of the imaging device is 80 to 89.9 degrees with respect to a normal line of the surface of the anodized alumina.

9. The method of inspecting an anodized alumina according to claim 6 , wherein the determining whether the aspect ratio (depth/pitch) of the pore of the anodized alumina is within the predetermined range based on the color information, comprises,

capturing an image of reflected light from the surface of the anodized alumina as an RGB signal, and

inspecting a shape of the pore of the anodized alumina based on information of the RGB signal.

10. The method of manufacturing an article having anodized alumina on a surface thereof according to claim 1 , wherein the inspecting the shape of the pore of the article having anodized alumina on the surface based on the color information comprises

capturing reflected light from the surface of the article having anodized alumina on the surface as an alumina RGB signal,

converting the RGB signal into an HSL color coordinate system, and

inspecting a shape of the pore of the article having anodized alumina on the surface based on information of the HSL color coordinate system.

11. The method of manufacturing an article having anodized alumina on a surface thereof according to claim 1 , further comprising following steps (a) to (e) before irradiating the surface of the article having anodized alumina on the surface thereof with light from the illumination device after the anodized alumina is formed:

(a) a step of anodizing a surface of a mirror-finished aluminum substrate in an electrolyte at a constant voltage, and forming an oxide film on the surface;

(b) a step of removing at least a portion of the oxide film, and forming a pore originating point of anodization on the surface of the aluminum substrate;

(c) a step of re-anodizing the surface of the aluminum substrate, on which the pore originating point is formed, in an electrolyte at a constant voltage, and forming an oxide film having a pore corresponding to the pore originating point on the surface;

(d) a step of expanding a diameter of the pore; and

(e) a step of repeatedly performing the step (c) and the step (d).

12. A method of manufacturing an optical film, comprising transferring a fine concave-convex structure of the article manufactured by the manufacturing method according to claim 1 to manufacture the optical film.

13. A device of inspecting an article having anodized alumina on a surface thereof, comprising: an illumination device that irradiates the surface of the article having anodized alumina with a structure having two or more pores in which a pore interval is less than or equal to a wavelength of visible light on the surface and reflects colored light with light; an imaging device that captures an image of reflected colored light from the surface of the article having anodized alumina on the surface; and an image processor that determines whether an aspect ratio (depth/pitch) of the pore of the anodized alumina is within a predetermined range based on color information obtained from the image captured by the imaging device, wherein in the capturing the image of the reflected colored light from the surface of the article having anodized alumina on the surface using the imaging device, the imaging device having an optical axis at an angle of 45 to 89.9 degrees with respect to a normal line of the surface of anodized alumina.

14. The device of inspecting an article according to claim 13 , wherein in the imaging device that captures an image of reflected light from the surface of the article having anodized alumina on the surface, an angle of an optical axis of the imaging device is 65 to 89.9 degrees with respect to a normal line of the surface of the anodized alumina.

15. The device of inspecting an article according to claim 13 , wherein in the imaging device that captures an image of reflected light from the surface of the article having anodized alumina on the surface, an angle of an optical axis of the imaging device is 80 to 89.9 degrees with respect to a normal line of the surface of the anodized alumina.

16. The device of inspecting an article according to claim 13 , wherein the image processor that inspects a shape of the pore based on the color information comprises

imaging device for capturing an image of reflected light from the surface of the article having anodized alumina on the surface as an RGB signal, and

inspecting device for inspecting a shape of the pore of the article having anodized alumina on the surface based on information of the RGB signal.

17. The device of inspecting an article according to claim 13 , wherein the image processor inspects a mold release agent attached to a fine concave-convex structure on the surface of the article based on the color information.

18. The device of inspecting an article according to claim 13 , wherein the image processor inspects a flow pattern of the article having a fine concave-convex structure on the surface of the article based on the color information.

19. A method of manufacturing an article having a fine concave-convex structure on a surface thereof, comprising: irradiating a surface of the article with the structure having two or more pores in which a pitch is less than or equal to a wavelength of visible light and reflecting colored light with light from an illumination device after the fine concave-convex structure is formed; capturing an image of reflected colored light from the surface of the article using an imaging device; acquiring color information from an image captured by the imaging device; and inspecting a shape of the fine concave-convex structure based on the color information, wherein in the capturing the image of the reflected colored light from the surface of the article having anodized alumina on the surface using the imaging device, the imaging device having an optical axis at an angle of 45 to 89.9 degrees with respect to a normal line of the surface of the fine concave-convex structure.

20. A method of inspecting an article having a fine concave-convex structure on a surface thereof, comprising: irradiating a surface of the article with the structure having two or more pores in which a pitch is less than or equal to a wavelength of visible light and reflecting colored light with light from an illumination device; capturing an image of reflected colored light from the surface of the article using an imaging device; acquiring color information from an image captured by the imaging device; and inspecting a shape of the fine concave-convex structure based on the color information, wherein in the capturing the image of the reflected colored light from the surface of the article having anodized alumina on the surface using the imaging device, the imaging device having an optical axis at an angle of 45 to 89.9 degrees with respect to a normal line of the surface of anodized alumina.

21. A method of inspecting an anodized alumina having two or more pores, comprising: irradiating a surface of the anodized alumina having two or more pores in which a pitch is less than or equal to a wavelength of visible light and reflecting colored light with light from an illumination device; capturing an image of reflected colored light from the surface of the anodized alumina using imaging device; acquiring color information from the image captured by the imaging device; and determining whether an aspect ratio (depth/pitch) of the pore of the anodized alumina is within a predetermined range based on the color information, wherein in the capturing the image of the reflected colored light from the surface of the article having anodized alumina on the surface using the imaging device, the imaging device having an optical axis at an angle of 45 to 89.9 degrees with respect to a normal line of the surface of anodized alumina.