# US 2014/0193607 A1 · White appearing anodized films and methods for forming the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0193607 A1 - Document ID: US20140193607A1 - Status: Published application - Kind: A1 - Application number: 14/240,252 - Filed: 2013-06-21 - Published: 2014-07-10 - Earliest claimed: 2012-06-22 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Lucy E. Browning; Stephen B. Lynch; Christopher D. Prest; Peter N. Russell-Clarke; Masashige Tatebe; Michael S. Nashner; Daniel T. McDonald; Brian S. Tryon; Jody R. Akana - Web page: https://patentgrep.com/patent/US20140193607A1 ## CPC - C25D 11/18: After-treatment, e.g. pore-sealing - B23K 26/354: by melting - B23K 26/355: {Texturing} - C25D 11/024: {Anodisation under pulsed or modulated current or potential} - C25D 11/04: of aluminium or alloys based thereon - C25D 11/045: {for forming AAO templates} - C25D 11/12: Anodising more than once, e.g. in different baths - Y10T 428/13: Hollow or container type article [e.g., tube, vase, etc.] - Y10T 428/24331: including nonapertured component - Y10T 428/24471: Crackled, crazed or slit - C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The embodiments described herein relate to forming anodized films that have a white appearance. In some embodiments, an anodized film having pores with light diffusing pore walls created by varying the current density during an anodizing process is described. In some embodiments, an anodized film having light diffusing micro-cracks created by a laser cracking procedure is described. In some embodiments, a sputtered layer of light diffusing aluminum is provided below an anodized film. In some embodiments, light diffusing particles are infused within openings of an anodized layer. ## Claims ### Claim at position 1 -36. (canceled) ### Claim 37 A method for providing an aluminum oxide layer having a predetermined thickness that appears white, the method comprising: modifying a structure of an aluminum oxide layer such that the aluminum oxide layer reflects substantially all wavelengths of visible light incident on an exposed surface of the aluminum oxide layer in a substantially diffuse manner, wherein the structure of the aluminum oxide layer comprises a plurality of substantially parallel pores extending inwardly from an exterior surface of the aluminum oxide layer, wherein the modifying comprises forming a plurality of micro-cracks within the internal structure by: applying a laser beam on the exposed surface to melt portions of the aluminum oxide layer forming a pattern of melted portions, and allowing the melted portions to cool and crystallize forming a pattern of crystallized aluminum oxide portions, wherein contraction of the crystallized aluminum oxide portions forms a plurality of micro-cracks that diffusely reflect nearly all wavelengths of visible light incident on an exposed surface of the crystallized aluminum oxide portions. ### Claim 38 (depends on 37) The method as recited in claim 37, further comprising: forming the aluminum oxide layer prior to the modifying by: (a) maintaining a current density at a first current density value for a first period of time, (b) changing the current density from the first current density value to a second current density value different from the first current density value, (c) maintaining the current density at the second current density value for a second period of time, and repeating (a)-(c) until a thickness of the aluminum oxide layer is at least the predetermined thickness, wherein the varying current density provides causes at least one of the plurality of pores to have a varying pore diameter. ### Claim 39 (depends on 38) The method as recited in claim 38, wherein the laser beam melts the portions of the aluminum oxide layer by increasing a temperature of the portions to at least a glass transition temperature of aluminum oxide. ### Claim 40 (depends on 37) The method as recited in claim 37, wherein the laser beam melts the portions of the aluminum oxide layer by increasing a temperature of the portions to at least a glass transition temperature of aluminum oxide. ### Claim 41 (depends on 37) The method as recited in claim 37, wherein the aluminum oxide layer is characterized as reflecting light having an Lab color space component values corresponding to an L value ranging from about 85 to 100 and a,b about zero. ### Claim 42 (depends on 37) The method as recited in claim 37, wherein the laser is a pulsed carbon dioxide laser. ### Claim 43 (depends on 42) The method as recited in claim 42, wherein the applying the laser beam includes raster scanning the laser beam on the exposed surface. ### Claim 44 (depends on 37) The method as recited in claim 37, further comprising: infiltrating particles into at least some of the plurality of pores, the infiltrated particles arranged to diffusely reflect light incident on the layer of aluminum oxide. ### Claim 45 (depends on 37) The method as recited in claim 37, wherein applying the laser beam on the exposed surface comprises scanning the laser beam over the exposed surface forming a plurality of spot areas within the aluminum oxide layer, each of the spot areas having a plurality of micro-cracks therein. ### Claim 46 (depends on 45) The method as recited in claim 45, wherein the spot areas are arranged in a predetermined pattern within the aluminum oxide layer. ### Claim 47 (depends on 37) The method as recited in claim 37, wherein the laser beam is a pulsed laser beam. ### Claim 48 A metal part having an anodized film with a white appearance disposed over an underlying surface of the metal part, the anodized film comprising: a porous metal oxide structure; a pattern of crystallized metal oxide portions within the porous metal oxide structure, the pattern of crystallized metal oxide portions having a plurality of micro-cracks, the plurality of micro-cracks having a plurality of visible light reflecting surfaces arranged in varied orientation with respect to an exposed surface of the anodized film, wherein the plurality of visible light reflecting surfaces diffusely reflect visible light incident the crystallized metal oxide portions, contributing an opaque and white appearance to the metal part. ### Claim 49 (depends on 48) The metal part as recited in claim 48, wherein the micro-cracks are on the scale of between about 0.5 and 30 microns in length. ### Claim 50 (depends on 48) The metal part as recited in claim 48, wherein the porous metal oxide structure allows visible light incident the exposed surface of the anodized film to pass therethrough and specularly reflect off the underlying surface, contributing a reflective bright appearance to the metal part. ### Claim 51 (depends on 50) The metal part as recited in claim 50, wherein the relative amount of diffuse reflection and specular reflection results in the anodized film having an L value ranging from about 85 to 100. ### Claim 52 (depends on 48) The metal part as recited in claim 48, wherein the anodized film further comprises: a plurality of openings diffusely reflecting wavelengths of visible light incident on an exposed surface of the anodized film. ### Claim 53 A method for producing an anodized film that appears white, the method comprising: creating a plurality of openings within the anodized film, the openings having an average size and shape suitable for accommodating a plurality of light reflective particles, the light reflective particles having a white appearance due to the presence of multiple visible light diffusing surfaces on the light reflective particles, wherein creating the openings comprises forming a plurality of micro-cracks within the anodized film; and infusing the plurality of light reflective particles within at least a portion of the openings, wherein the white appearance of the light reflective particles imparts a white appearance to the anodized film. ### Claim 54 (depends on 53) The method as recited in claim 53, wherein directing a laser beam at the anodized film forms the plurality of micro-cracks. ### Claim 55 (depends on 54) The method as recited in claim 54, wherein the laser beam is scanned over a top surface of the anodized film forming a plurality of spot areas within the anodized film, each of the spot areas having a plurality of micro-cracks therein. ### Claim 56 (depends on 54) The method as recited in claim 54, wherein the laser beam is a pulsed laser beam.