Anodized films with branched pore structures

Patent metadata

Field	Value
Publication number	US-9487879-B2
Application number	US-201514694971-A
Country	US
Kind code	B2
Filing date	Apr 23, 2015
Priority date	Sep 27, 2013
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

The embodiments described herein relate to anodizing and anodized films. The methods described can be used to form opaque and white anodized films on a substrate. In some embodiments, the methods involve forming anodized films having branched pore structures. The branched pore structure provides a light scattering medium for incident visible light, imparting an opaque and white appearance to the anodized film. In some embodiments, the methods involve infusing metal complex ions within pores of an anodized. Once within the pores, the metal complex ions undergo a chemical change forming metal oxide particles. The metal oxide particles provide a light scattering medium for incident visible light, imparting an opaque and white appearance to the anodized film. In some embodiments, aspects of the methods for creating irregular or branched pores and methods for infusing metal complex ions within pores are combined.

First claim

What is claimed is:

1. A protective film on a metal part, the protective film comprising:
a barrier layer having an exterior surface corresponding to an exterior surface of the metal part, the barrier layer having branched structures positioned only within the barrier layer and having substantially no anodic pores, wherein the branched structures are arranged in a branching pattern that diffusely reflects visible wavelengths of light incident on the exterior surface and imparts a white appearance to the barrier layer; and
a porous anodic layer positioned adjacent the metal part and providing structural support for the barrier layer.

2. The protective film of claim 1 , wherein the porous anodic layer comprises pores arranged in parallel with top ends adjacent to the branched structures and bottom ends adjacent to an underlying metal surface of the metal part.

3. The protective film of claim 1 , wherein the barrier layer has indented portions on the exterior surface of the barrier layer.

4. The protective film of claim 1 , wherein the branched structures are formed through an entire thickness of the barrier layer.

5. The protective film of claim 1 , wherein a thickness of the porous anodic layer is greater than a thickness of the barrier layer.

6. The protective film of claim 1 , wherein the porous anodic layer includes anodic pores having terminal ends adjacent the metal part, wherein at least some of the terminal ends have bulbous shapes.

7. The protective film of claim 6 , wherein the bulbous-shaped terminal ends provide a second light scattering medium that contributes a white appearing aspect to the protective film.

8. The protective film of claim 1 , wherein the porous anodic layer includes anodic pores having irregularly shaped pore walls that contributes a white appearing aspect to the protective film.

9. The protective film of claim 1 , wherein the barrier layer has an average thickness of about 1 micrometer.

10. An enclosure for an electronic device, the enclosure comprising:
a protective film positioned on a surface of a metal substrate, the protective film comprising:
a porous anodic layer adjacent the surface of the metal substrate; and
a barrier layer positioned on the porous anodic layer, the barrier layer having branched structures positioned only within the barrier layer, wherein the branched structures are arranged in a branching pattern that diffusely reflects visible wavelengths of light incident on the protective film, thereby imparting a white appearance to the protective film.

11. The enclosure of claim 10 , wherein the barrier layer has substantially no anodic pores.

12. The enclosure of claim 10 , wherein anodic pores of the porous anodic layer are substantially parallel with respect to each other and are substantially perpendicular with respect to an external surface of an external surface of the protective film.

13. The enclosure of claim 10 , wherein a thickness of the porous anodic layer is greater than a thickness of the barrier layer.

14. The enclosure of claim 10 , wherein some of the branched structures have an elongated shape.

15. The enclosure of claim 10 , wherein the porous anodic layer includes anodic pores having terminal ends adjacent the metal substrate, wherein at least some of the terminal ends have bulbous shapes.

16. The enclosure of claim 15 , wherein diameters of the bulbous-shaped terminal ends are greater than diameters of remaining portions of the anodic pores.

17. The enclosure of claim 10 , wherein the porous anodic layer includes anodic pores, an average length of the branched structures less than an average length of the anodic pores.

18. A metal oxide film covering a surface of a substrate, the metal oxide film comprising:
a porous anodic layer adjacent the surface of the substrate, the porous anodic layer having anodic pores with metal oxide particles positioned therein; and
a barrier layer adjacent the porous anodic layer, the barrier layer having branched structures positioned only within the barrier layer and having substantially no anodic pores, the branched structures arranged in a branching pattern that diffusely reflects visible wavelengths of light incident on the metal oxide film and imparts a white appearance to the barrier layer.

19. The metal oxide film of claim 18 , wherein the metal oxide particles diffusely reflect visible light that reach the metal oxide particles imparting a white appearance to the porous anodic layer.

20. The metal oxide film of claim 18 , wherein the metal oxide particles comprise titanium oxide particles.

Assignees

• Apple Inc

Inventors

• Tatebe Masashige
• Akana Jody R
• Oshima Takahiro
• Russell-Clarke Peter N
• Sakoguchi Masayuki
• Hara Kenji

Classifications

• C25D11/246

  for sealing layers · CPC title

• C25D11/16

  Pretreatment {, e.g. desmutting} · CPC title

• C25D11/12 Primary

  Anodising more than once, e.g. in different baths · CPC title

• C25D11/20

  Electrolytic after-treatment · CPC title

• C25D11/22

  for colouring layers · CPC title