# US 12,005,706 B2 · Inkjet printing device, printing method of bipolar element, and manufacturing method of display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,005,706 B2 - Document ID: US12005706B2 - Status: Granted - Kind: B2 - Application number: 17/786,931 - Filed: 2020-06-05 - Published: 2023-02-16 - Granted: 2024-06-11 - Earliest claimed: 2019-12-17 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., LTD. - Inventors: An Na Ryu; Jin Oh Kwag; Heung Cheol Jeong - Web page: https://patentgrep.com/patent/US12005706B2 ## CPC - B41J 2/04561: {detecting presence or properties of a drop in flight} - B41J 2/14: Structure thereof {only for on-demand ink jet heads} - B41J 2/0456: {detecting drop size, volume or weight} - B41J 2/04586: {controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type} - B41J 2/125: Sensors, e.g. deflection sensors {(nozzle clogging detection for cleaning reasons B41J2/16579; detection for compensation for failed nozzles B41J2/2139)} - B41J 2/18: Ink recirculation systems - B41M 5/00: Duplicating or marking methods; Sheet materials for use therein (by using light-sensitive materials G03; electrography, magnetography G03G {; repeatedly usable boards or tablets for writing or drawing B43L1/00}) - B41M 5/0023: {Digital printing methods characterised by the inks used (inks per se C09D11/00)} - C09D 11/322: Pigment inks - G01N 21/47: Scattering, i.e. diffuse reflection (G01N21/25, G01N21/41 take precedence {G01N21/55 takes precedence}) - G01N 33/32: Paints; Inks - B41J 2002/14354: {Sensor in each pressure chamber} - B41J 2202/09: Ink jet technology used for manufacturing optical filters - B41J 2202/12: with ink circulating through the whole print head - B41J 2202/20: Modules - H10H 20/01: Manufacture or treatment - H10W 90/00: Package configurations - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract An inkjet printing device includes a stage; an inkjet head disposed above the stage and comprising nozzles through which ink is discharged, the ink including bipolar elements extending in a direction; an ink circulation part which supplies the ink to the inkjet head, and to which the ink remaining after being discharged from the inkjet head is supplied; and at least one sensing part disposed between the inkjet head and the ink circulation part and sensing a number of the bipolar elements that are discharged through the nozzles. ## Claims ### Claim 1 An inkjet printing device comprising: a stage; an inkjet head disposed above the stage and comprising nozzles through which ink is ejected, the ink comprising bipolar elements extending in a direction; an ink circulation part supplying the ink to the inkjet head, and supplied with the ink remaining after the ink is ejected from the inkjet head; and at least one sensing part disposed between the inkjet head and the ink circulation part and measuring a number of the bipolar elements ejected through the nozzles. ### Claim 2 (depends on 1) The inkjet printing device of claim 1, wherein the at least one sensing part comprises a light emitting part emitting light to the ink, and a light receiving part spaced apart from and facing the light emitting part and receiving the light emitted from the light emitting part. ### Claim 3 (depends on 2) The inkjet printing device of claim 2, wherein an outer wall of the nozzles is made of at least one transparent material, at least part of the light emitted to the ink is scattered by the bipolar elements, and the light receiving part measures the number of the bipolar elements by receiving the light emitted from the light emitting part and the scattered light. ### Claim 4 (depends on 3) The inkjet printing device of claim 3, wherein the at least one sensing part detects a change in the number of the bipolar elements in the ejected ink, and the ink circulation part receives the detected change in the number of bipolar elements from the at least one sensing part. ### Claim 5 (depends on 3) The inkjet printing device of claim 3, further comprising: connection tubes connecting the ink circulation part and the inkjet head, wherein the at least one sensing part is disposed on the connection tube. ### Claim 6 (depends on 2) The inkjet printing device of claim 2, wherein the inkjet head comprises: a base part; an ejecting part which is a portion of the base part and in which the nozzles are disposed; and an inner tube supplied with the ink, the light emitting part and the light receiving part of the at least one sensing part disposed on the ejecting part, and at least one of the nozzles is disposed between the light emitting part and the light receiving part of the at least one sensing part. ### Claim 7 (depends on 6) The inkjet printing device of claim 6, wherein each of the nozzles comprises: an inlet connected to the inner tube and through which the ink is introduced, and an outlet connected to the inlet and through which the ink is ejected, the inkjet head further comprises an actuator disposed on the ejecting part and surrounding the nozzles, and the at least one sensing part comprises a first sensing part disposed between the actuator and the inner tube and adjacent to the inlet of the at least one of the nozzles. ### Claim 8 (depends on 7) The inkjet printing device of claim 7, wherein the at least one sensing part further comprises a second sensing part spaced apart from the first sensing part, and the actuator is disposed between the first and second sensing parts and adjacent to the outlet. ### Claim 9 (depends on 7) The inkjet printing device of claim 7, wherein the at least one sensing part further comprises a third sensing part in which the light emitting part and the light receiving part are disposed on the base part, and the inner tube is disposed between the third sensing part and the base part. ### Claim 10 (depends on 6) The inkjet printing device of claim 6, wherein the light receiving part is disposed in the ejecting part, the light emitting part is disposed on an outer surface of the base part, and the at least one sensing part further comprises a light transmitting part disposed in the ejecting part, disposed between the at least one of the nozzles and the light emitting part, and transmitting the light emitted from the light emitting part into the at least one of the nozzles. ### Claim 11 (depends on 2) The inkjet printing device of claim 2, wherein the inkjet head further comprises an electric field generating electrode generating an electric field in the nozzles. ### Claim 12 A printing method of a bipolar element, comprising: preparing an ink circulation part storing ink in which bipolar elements are dispersed and supplying the ink to an inkjet head; ejecting the ink from the inkjet head and measuring a number of bipolar elements in the ejected ink; and controlling the number of the bipolar elements in the ink supplied to the inkjet head in case that the number of the bipolar elements in the ink exceeds a reference set value. ### Claim 13 (depends on 12) The printing method of claim 12, wherein the measuring of the number of the bipolar elements is performed by at least one sensing part disposed between the inkjet head and the ink circulation part, and the at least one sensing part comprises: a light emitting part emitting light to the ink, and a light receiving part spaced apart from and facing the light emitting part and receiving the light emitted from the light emitting part. ### Claim 14 (depends on 13) The printing method of claim 13, wherein at least part of the light emitted to the ink is scattered by the bipolar elements, and the light receiving part measures the number of the bipolar elements by being irradiated with the light emitted from the light emitting part and the scattered light. ### Claim 15 (depends on 13) The printing method of claim 13, wherein the controlling of the number of the bipolar elements in the ink comprises receiving, at the ink circulation part, a change in the number of the bipolar elements detected by the at least one sensing part, and controlling, at the ink circulation part, a degree of dispersion of the bipolar elements in the ink. ### Claim 16 (depends on 13) The printing method of claim 13, further comprising spraying the ink ejected from the inkjet head onto a target substrate and disposing the bipolar elements on the target substrate. ### Claim 17 (depends on 16) The printing method of claim 16, wherein the spraying of the bipolar elements onto the target substrate is conducted using an inkjet printing device, wherein the inkjet printing device comprises: a stage; the inkjet head disposed above the stage and comprising nozzles through which the ink, is ejected, the ink comprising the bipolar elements extending in a direction; the ink circulation part supplying the ink to the inkjet head, and supplied with the ink remaining after the ink is ejected from the inkjet head; and the at least one sensing part disposed between the inkjet head and the ink circulation part and measuring the number of the bipolar elements ejected through the nozzles. ### Claim 18 A method of manufacturing a display device, comprising: preparing a target substrate on which a first electrode and a second electrode are formed; spraying ink in which light emitting elements are dispersed onto the target substrate while controlling a number of the light emitting elements dispersed in the ink; and disposing the light emitting elements onto the first electrode and the second electrode. ### Claim 19 (depends on 18) The method of claim 18, wherein the controlling of the number of the light emitting elements dispersed in the ink comprises: measuring the number of the light emitting elements in the ink sprayed onto the target substrate and controlling the number of the light emitting elements dispersed in the ink in case that the number of the light emitting elements in the ink exceeds a reference set value. ### Claim 20 (depends on 19) The method of claim 19, wherein the measuring of the number of the light emitting elements comprises: emitting light to the ink; receiving the light and scattered light scattered by the light emitting element from at least part of the light emitted to the ink; and measuring the number of the light emitting elements from the light and the scattered light.