# US 11,079,580 B2 · Exposure optics and device for producing a three-dimensional object > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,580 B2 - Document ID: US11079580B2 - Status: Granted - Kind: B2 - Application number: 15/771,261 - Filed: 2016-10-28 - Published: 2018-11-01 - Granted: 2021-08-03 - Earliest claimed: 2015-11-04 - Assignees: EOS GmbH Electro Optical Systems - Applicants: EOS GmbH Electro Optical Systems - Inventors: Hans Perret; Stephan Gronenborn - Web page: https://patentgrep.com/patent/US11079580B2 ## CPC - B41J 2/451: {Special optical means therefor, e.g. lenses, mirrors, focusing means} - B22F 10/28: Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] - B22F 12/44: characterised by the configuration of the radiation means - B22F 12/45: Two or more - B29C 64/153: using layers of powder being selectively joined, e.g. by selective laser sintering or melting - B29C 64/264: Arrangements for irradiation - B29C 64/268: using laser beams; using electron beams [EB] - B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor - G02B 13/22: Telecentric objectives or lens systems - G02B 19/0009: {having refractive surfaces only} - G03F 7/2053: {using a laser (ablative removal B41C)} - G03F 7/2055: {for the production of printing plates; Exposure of liquid photohardening compositions} - G03F 7/70416: {2.5D lithography} - B22F 12/40: Radiation means - B22F 12/41: characterised by the type, e.g. laser or electron beam - B22F 12/47: parallel to the deposition plane - B22F 12/49: Scanners - B23K 26/0665: {by beam condensation on the workpiece, e.g. for focusing} - B33Y 10/00: Processes of additive manufacturing - Y02P 10/25: Process efficiency - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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) - 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 - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract An exposure optics serves as an equipping and/or retrofitting optics for a device for producing a three-dimensional object by selectively solidifying building material, layer by layer. The exposure optics includes at least a first object-sided lens system having a first focal length f1 and a second image-sided lens system having a second focal length f2, which lens systems can be arranged in the beam path of the radiation emitted by the radiation source. The focal plane of the first lens system and the focal plane of the second lens system coincide in a plane between the two lens systems. The focal length f1 of the first lens system is equal to or greater than the focal length f2 of the second lens system. The exposure optics is designed and can be arranged such that the electromagnetic radiation is incident substantially perpendicular on the working surface. ## Claims ### Claim 1 An exposure optics as an equipping and/or retrofitting optics for a device for producing a three-dimensional object by selectively solidifying building material, layer by layer, at positions that correspond to a cross-section of the object to be produced in the respective layer by electromagnetic radiation, wherein the device comprises a radiation source capable of emitting the electromagnetic radiation in a plurality of beams each of which is suited to cause solidification of the building material at positions of a layer of the building material applied in a working surface of the device, the positions corresponding to the cross-section of the object to be produced, when impinging on the positions, the exposure optics comprising: at least a first beam source facing lens system having a first focal length f1 and a second working surface facing lens system having a second focal length f2, the lens systems being arranged in the beam paths of the radiation emitted by the radiation source, the beam paths being in a straight linear array between the lens systems, the focal plane of the first lens system and the focal plane of the second lens system coinciding in a plane between the two lens systems; and the focal length f1 of the first lens system is equal to or greater than the focal length f2 of the second lens system, and the beams from the working surface sided lens system are focused to impinge substantially perpendicular on the working surface. ### Claim 2 A device for producing a three-dimensional object by selectively solidifying building material, layer by layer, at positions that correspond to a cross-section of the object to be produced in the respective layer by electromagnetic radiation, comprising: a radiation source capable of emitting electromagnetic radiation that is suited to cause solidification of the building material at positions of a layer of the building material applied in a working surface of the device, the positions corresponding to the cross-section of the object to be produced, when impinging on those positions; and an exposure optics having at least a first object-sided lens system having a first focal length f1 and a second image-sided lens system having a second focal length f2, the lens systems being arranged in a beam path of the radiation emitted by the radiation source, wherein the focal plane of the first lens system and the focal plane of the second lens system coincide in a plane between the two lens systems; wherein the focal length f1 of the first lens system is equal to or greater than the focal length f2 of the second lens system; wherein the exposure optics is designed and arranged so that the electromagnetic radiation is incident substantially perpendicular on the working surface; and wherein the radiation source and the exposure optics are movable across the working surface to selectively solidify a layer of the building material applied in the working surface. ### Claim 3 (depends on 2) The device according to claim 2, wherein the radiation source is formed by lasers which are grouped as modules. ### Claim 4 (depends on 2) The device according to claim 2, wherein the exposure optics is movably arranged in a process chamber of the device. ### Claim 5 (depends on 2) The device according to claim 2, wherein the focal length f2 of the second lens system is smaller than a minimum free working distance (FWD). ### Claim 6 (depends on 2) The device according to claim 2, wherein the radiation source and/or a further exposure optics arranged between the radiation source and the exposure optics are configured such that the radiation is incident on the first lens system substantially perpendicular. ### Claim 7 (depends on 3) The device according to claim 3, wherein the lasers are VCSELs. ### Claim 8 (depends on 3) The device according to claim 3, wherein each module comprises at least two laser arrays. ### Claim 9 (depends on 2) The device according to claim 2, wherein the second lens system of the exposure optics comprises at least two curved surfaces, and wherein at least one of the curved surfaces is aspheric. ### Claim 10 (depends on 2) The device according to claim 2, wherein the second lens system of the exposure optics comprises at least two curved surfaces and a minimum distance and/or a center thickness between the two surfaces is greater than a quarter of the focal length f2. ### Claim 11 (depends on 2) The device according to claim 2, wherein the second lens system of the exposure optics comprises at least two curved surfaces, wherein at least one of the curved surfaces is spherical and for whose radius of curvature R applies: R