# US 7,608,387 B1 · Method for fabricating mold core > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,387 B1 - Document ID: US7608387B1 - Status: Granted - Kind: B1 - Application number: 12/354,096 - Filed: 2009-01-15 - Published: 2009-11-12 - Granted: 2009-10-27 - Earliest claimed: 2008-05-06 - Assignees: Hon Hai Precision Industry Co., Ltd. - Inventors: Sei-Ping Louh - Web page: https://patentgrep.com/patent/US7608387B1 ## CPC - B23P 15/24: dies (B21C3/18, B21C25/10, B21D37/20 take precedence) - G03F 7/0017: {for the production of embossing, cutting or similar devices; for the production of casting means} - Y10S 430/143: Electron beam - Y10S 430/146: Laser beam - B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q) - G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract An exemplary method for fabricating a mold core includes the following steps. First, a substrate is provided. Second, a photo resist layer is formed on the substrate, the photo resist layer has a top surface. Third, the photo resist layer is etched using a direct writing process to form the top surface thereof into a substantially aspherical stepped surface. Lastly, the photo resist layer is softened using a reflow process to transform the substantially aspherical stepped surface into a substantially aspherical smooth molding surface. Thereby, a mold core having the substantially aspherical smooth molding surface is obtained. ## Claims ### Claim 1 A method for fabricating a mold core comprising: providing a substrate; forming a photo resist layer on the substrate, the photo resist layer having a top surface; etching the photo resist layer using a direct writing process to form the top surface thereof into a substantially aspherical stepped surface; and softening the photo resist layer using a reflow process to transform the substantially aspherical stepped surface into a substantially aspherical smooth molding surface, thereby obtaining a mold core having the substantially aspherical smooth molding surface. ### Claim 2 (depends on 1) The method of claim 1, wherein a profile of the aspheical smooth molding surface is represented by the following equation: y = f ⁢ ⁢ ( x ) = cx 2 1 + 1 - ( 1 + k ) ⁢ ⁢ c 2 ⁢ ⁢ x 2 + a 4 ⁢ ⁢ x 4 + a 6 ⁢ ⁢ x 6 + a 8 ⁢ ⁢ x 8 + … + a n ⁢ ⁢ x n , x represents an X coordinate of each point on the aspherical surface, y represents a Y coordinate of each point on the aspherical surface, a4, a6, a8, an represent coefficients of higher orders of the equation, c represents the curvature at the vertex of the profile, k represents the conic constant, n represents a positive integer and tends to infinity. ### Claim 3 (depends on 2) The method of claim 2, wherein a profile of the substantially aspherical stepped surface comprises a plurality of contiguous steps, each step having a vertical line parallel with the Y axis direction and a horizontal line parallel with the X axis direction, the vertical line and the horizontal line intersecting at an outward intersecting point, each step adjoining two proximate neighboring steps at a first and a second inward intersecting points, and the width and the height of each step of the substantially aspherical stepped surface are determined by the following steps: determining an outward intersecting point of a given step, the outward intersecting point being not on the aspherical surface; determining a first inward intersecting point of the given step, the first inward intersecting point having a same Y coordinate as the outward intersecting point and being at an opposite side of the aspherical surface to the outward intersecting point, a point on the aspherical surface with the same Y coordinate as the outward intersecting point being equidistant from the outward intersecting point and the first inward intersecting point, thereby obtaining the width of the given step which is equal to a distance between the outward intersecting point and the first inward intersecting point; and determining a second inward intersecting point of the given step, the second inward intersecting point having a same X coordinate as the outward intersecting point and being at an opposite side of the aspherical surface to the outward intersecting point, a point on the aspherical surface with the same X coordinate as the outward intersecting point being equidistant from the outward intersecting point and the second inward intersecting point, thereby obtaining the height of the given step which is equal to a distance between the outward intersecting point and the second inward intersecting point. ### Claim 4 (depends on 2) The method of claim 2, wherein a profile of the substantially aspherical stepped surface comprises a plurality of contiguous steps, each step having a vertical line parallel with the Y axis direction and a horizontal line parallel with the X axis direction, the vertical line and the horizontal line intersecting at an outward intersecting point, each step adjoining two proximate neighboring steps at a first and a second inward intersecting points, and the width and the height of each step of the substantially aspherical stepped surface are determined by the following steps: determining a first inward intersecting point of a given step, the first inward intersecting point being not on the aspherical surface; determining an outward intersecting point of the given step, the outward intersecting point having a same Y coordinate as the first inward intersecting point and being at an opposite side of the aspherical surface to the first inward intersecting point, a point on the aspherical surface with the same Y coordinate as the first inward intersecting point being equidistant from the first inward intersecting point and the outward intersecting point, thereby obtaining the width of the given step which is equal to a distance between the outward intersecting point and the first inward intersecting point; and determining a second inward intersecting point of the given step, the second inward intersecting point having a same X coordinate as the outward intersecting point and being at an opposite side of the aspherical surface to the outward intersecting point, a point on the aspherical surface with the same X coordinate as the outward intersecting point being equidistant from the outward intersecting point and the second inward intersecting point, thereby obtaining the height of the given step which is equal to a distance between the outward intersecting point and the second inward intersecting point. ### Claim 5 (depends on 2) The method of claim 2, wherein a profile of the substantially aspherical stepped surface includes a plurality of contiguous steps, each step having a vertical line parallel with the Y axis direction and a horizontal line parallel with the X axis direction, the vertical line and the horizontal line intersecting at an outward intersecting point, each step adjoining two proximate neighboring steps at a first and a second inward intersecting point, and the width and the height of each step of the substantially aspherical stepped surface is determined by the following steps: determining a second inward intersecting point of a given step, the second inward intersecting point being not on the aspherical surface; determining an outward intersecting point of the given step, the outward intersecting point having a same X coordinate as the second inward intersecting point and being at an opposite side of the aspherical surface to the second inward intersecting point, a point on the aspherical surface with the same X coordinate as the second inward intersecting point being equidistant from the second inward intersecting point and the outward intersecting point, thereby obtaining the height of the given step which is equal to a distance between the outward intersecting point and the second inward intersecting point; and determining a first inward intersecting point of the given step, the first inward intersecting point having a same Y coordinate as the outward intersecting point and being at an opposite side of the aspherical surface to the outward intersecting point, a point on the aspherical surface with the same Y coordinate as the outward intersecting point being equidistant from the outward intersecting point and the first inward intersecting point, thereby obtaining the width of the given step which is equal to a distance between the outward intersecting point and the first inward intersecting point. ### Claim 6 (depends on 1) The method of claim 1, wherein the direct writing process is a laser direct writing process. ### Claim 7 (depends on 6) The method of claim 6, wherein the height of each step is controlled by controlling the light intensity of a laser beam, and the width of each step is controlled by the scan area of the laser beam. ### Claim 8 (depends on 7) The method of claim 7, wherein the photo resist layer is progressively etched by scanning the photo resist layer using the laser beam along a direction parallel to the X coordinate axis. ### Claim 9 (depends on 7) The method of claim 7, wherein the photo resist layer is progressively etched by progressively reducing the scan area of the laser beam. ### Claim 10 (depends on 1) The method of claim 1, wherein the substrate is comprised of a material selected from a group consisting of plastic, silicon carbide, tungsten carbide, quartz glass and metal. ### Claim 11 (depends on 1) The method of claim 1, wherein the photo resist layer is formed by a method selected from the group consisting of spin coating, droplet dispensing and spray coating. ### Claim 12 (depends on 1) The method of claim 1, wherein the direct writing process is an electron-beam direct writing process. ### Claim 13 (depends on 12) The method of claim 12, wherein the height of each step is controlled by controlling the intensity of an electron beam, and the width of each step is controlled by the scan area of the electron beam. ### Claim 14 (depends on 13) The method of claim 13, wherein the photo resist layer is progressively etched by scanning the photo resist layer using the electron beam along a direction parallel to the X coordinate axis. ### Claim 15 (depends on 13) The method of claim 13, wherein the photo resist layer is progressively etched by progressively reducing the scan area of the electron beam. ### Claim 16 (depends on 1) The method of claim 1, further comprising hard baking the photo resist layer after the softening step.