# US 2019/0169061 A1 · Controlled crystallization of glass ceramics for electronic devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0169061 A1 - Document ID: US20190169061A1 - Status: Published application - Kind: A1 - Application number: 16/007,851 - Filed: 2018-06-13 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Christopher D. Jones; Dale N. Memering - Web page: https://patentgrep.com/patent/US20190169061A1 ## CPC - C03B 32/02: Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)} - C03B 23/02: Re-forming glass sheets - C03B 23/0302: {between opposing full-face shaping moulds} - C03B 23/0307: {Press-bending involving applying local or additional heating, cooling or insulating means} - H04M 1/02: Constructional features of telephone sets - H05K 5/03: Covers - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract Methods are disclosed directed to a controlled crystallization (ceramic particle growth) of a shaped glass ceramic workpiece. The physical and chemical properties of the shaped glass ceramic of the present invention may be specified or tailored by shaping or machining the workpiece during or in combination with a controlled crystallization process that nucleates (precipitates) ceramic particles from a glass material. For example, in one embodiment, a non-crystalline amorphous solid may be heated above a transition temperature and shaped (e.g., molded, pressed, or the like). Ceramic particles may be precipitated within the solid during at least one of the heating or the shaping, thereby forming a shaped glass ceramic. ## Claims ### Claim 1 A method for forming a shaped glass ceramic, comprising: growing a ceramic crystalline structure to a first size, the ceramic crystalline structure grown within a glass workpiece; after growing the ceramic crystalline structure to the first size, mechanically shaping the glass workpiece; and while mechanically shaping the glass workpiece, growing the ceramic crystalline structure to a second size that is larger than the first size. ### Claim 2 (depends on 1) The method of claim 1, wherein: growing the ceramic crystalline structure to the second size further comprises controlling a rate of thermal energy received by the glass workpiece while mechanically shaping the glass workpiece; and controlling the rate of thermal energy increases an average density of the ceramic crystalline structure. ### Claim 3 (depends on 2) The method of claim 2, wherein: the glass workpiece includes a nucleation agent; and the rate of thermal energy is based on a concentration of the nucleation agent within the glass workpiece. ### Claim 4 (depends on 1) The method of claim 1, wherein the method further comprises cooling the glass workpiece after mechanically shaping the glass workpiece to limit the growth of the ceramic crystalline structure to the second size. ### Claim 5 (depends on 1) The method of claim 1, wherein the glass workpiece having the ceramic crystalline structure of the second size exhibits an enhanced resistance to impact with respect to the glass workpiece having the ceramic crystalline structure of the first size. ### Claim 6 (depends on 1) The method of claim 1, wherein: mechanically shaping occurs at a first temperature that is above a transition temperature of the glass workpiece; and growing the ceramic crystalline structure to the second size occurs at a second temperature that is either above or below the transition temperature. ### Claim 7 (depends on 1) The method of claim 1, wherein the shaped glass ceramic is a cover glass that defines an external surface for an electronic device. ### Claim 8 (depends on 7) The method of claim 7, wherein the cover glass is a light-transmissive member defining a contoured exterior surface of the electronic device. ### Claim 9 (depends on 1) The method of claim 1, wherein prior to growing the ceramic crystalline structure to the first size, the glass workpiece is a substantially non-crystalline amorphous solid. ### Claim 10 A method for forming a shaped glass ceramic, comprising: pressing, in a mold, a glass material at a temperature at or above a transition temperature; while pressing the glass material, maintaining the glass material at the temperature above the transition temperature, thereby growing a crystalline structure within the glass material; and while pressing the glass material, cooling the glass material below the transition temperature, thereby inhibiting growth of the crystalline structure beyond a predetermined size. ### Claim 11 (depends on 10) The method of claim 10, wherein growing the crystalline structure within the glass material comprises precipitating ceramic particles while pressing the glass material in the mold above the transition temperature. ### Claim 12 (depends on 10) The method of claim 10, wherein pressing the glass material in the mold comprises: exerting a mechanical force on the glass material, thereby conforming the glass material to a contoured shape of the mold; and reducing the mechanical force on the glass material after the glass material conforms to the mold while maintaining the temperature at or above the transition temperature. ### Claim 13 (depends on 10) The method of claim 10, wherein the crystalline structure comprises a mixture of aluminum oxide, silicon oxide, and at least one of: lithium oxide; magnesium oxide; or zinc oxide. ### Claim 14 (depends on 10) The method of claim 10, wherein the glass material comprises a nucleation agent. ### Claim 15 (depends on 10) The method of claim 10, wherein the glass material, before the pressing, is substantially free of crystallite structures. ### Claim 16 An electronic device comprising: an enclosure; and a cover glass affixed to the enclosure and having crystalline structures therein; wherein: the crystalline structures are formed within the cover glass when the cover glass is mechanically shaped; and the crystalline structures enhance a resistance to impact as compared to a cover glass lacking the crystalline structures. ### Claim 17 (depends on 16) The electronic device of claim 16, wherein: the electronic device further comprises a display configured to depict a graphical output; and the cover glass is positioned over the display. ### Claim 18 (depends on 16) The electronic device of claim 16, wherein: the cover glass is mechanically shaped by being heated to a temperature and pressed while at the temperature; and the cover glass is a glass ceramic. ### Claim 19 (depends on 18) The electronic device of claim 18, wherein the temperature is at or above a transition temperature of the cover glass. ### Claim 20 (depends on 19) The electronic device of claim 19, wherein the crystalline structures have a crystalline growth temperature that is below the transition temperature.