# US 2019/0168251 A1 · Method and apparatus for controlling jet dispensing by displacement measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168251 A1 - Document ID: US20190168251A1 - Status: Published application - Kind: A1 - Application number: 16/304,360 - Filed: 2017-05-24 - Published: 2019-06-06 - Earliest claimed: 2016-05-26 - Assignees: Mycronic AB - Applicants: Mycronic AB - Inventors: Daniel BREVEMARK - Web page: https://patentgrep.com/patent/US20190168251A1 ## CPC - B05C 5/0225: {characterised by flow controlling means, e.g. valves, located proximate the outlet (B05C5/0258, B05C5/0275 take precedence; supply valves upstream the coating head B05C11/1036)} - B05B 1/083: {the pulsating mechanism comprising movable parts} - B05B 12/082: {responsive to a condition of the discharged jet or spray, e.g. to jet shape, spray pattern or droplet size} - B05C 11/1034: {specially designed for conducting intermittent application of small quantities, e.g. drops, of coating material (B05C5/0225, B05C11/1026 take precedence)} - H05K 3/125: {by ink-jet printing} - B05B 12/08: responsive to condition of liquid or other fluent material {to be} discharged, of ambient medium or of target {; responsive to condition of spray devices or of supply means, e.g. pipes, pumps or their drive means} - B05C: APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (spraying apparatus, atomising apparatus, nozzles B05B; plant for applying liquids or other fluent materials to objects by electrostatic spraying B05B5/08) - B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract A method for jetting a viscous medium onto a substrate is disclosed. The method includes providing viscous medium to a jetting chamber of an ejector, operating an impacting device to impact a volume of the viscous medium in the chamber such that viscous medium is jetted through a nozzle, connected to the chamber, towards the substrate, and monitoring a displacement of the impacting device during impact. An ejector and a system comprising such an ejector and a control unit is also disclosed. The monitoring of the displacement allows for the operation of the impacting device to be controlled accordingly, thereby providing for an improved control of the jetting process. ## Claims ### Claim at position 1 1-19. (canceled) ### Claim 20 A method for jetting a viscous medium onto a substrate, the method comprising: providing viscous medium to a jetting chamber of an ejector, said jetting chamber comprising an open connection, or inlet, to the channel of the feeder providing the viscous medium to the chamber; operating an impacting device configured to be in direct contact with the viscous medium to directly impact and displace a volume of the viscous medium in the chamber such that viscous medium is jetted through a nozzle, connected to the chamber, towards the substrate; and monitoring a displacement of the impacting device. ### Claim 21 (depends on 20) The method according to claim 20, wherein said action of monitoring comprises monitoring a position of the impacting device to thereby determine the returning position of the forward impact movement of the impacting device. ### Claim 22 (depends on 20) The method according to claim 20, wherein said action of monitoring comprises monitoring a sequence of positions of the impacting device with respect to its assembly housing in the time domain during at least one of the forward impact movement of the impacting device and the controlled retraction of the impacting device to the initial position. ### Claim 23 (depends on 20) The method according to claim 20, wherein the monitored displacement is used as input data affecting subsequent operation of the impacting device. ### Claim 24 (depends on 20) The method according to claim 20, wherein the step of monitoring the displacement of the impacting device comprises: determining at least one of position(s), velocity, acceleration and length of a stroke of the impacting device during the impact; and calculating a correction factor based on a comparison between the determined position(s), velocity, acceleration and/or length of the stroke and at least one reference value; wherein the correction factor is used for adjusting subsequent operation of the impacting device. ### Claim 25 (depends on 20) The method according to claim 20, wherein the step of monitoring the displacement of the impacting device comprises: determining a length of a stroke of the impacting device during the impact; and calculating a correction factor based on a comparison between the determined length of the stroke and a reference length value; wherein the correction factor is used for statistical processing and correction. ### Claim 26 (depends on 20) The method according to claim 20, wherein the step of monitoring the displacement of the impacting device comprises: determining at least one of the position(s), velocity and acceleration of the impacting device during the impact; and calculating a correction factor based on a comparison between the determined position(s), velocity and/or acceleration and a reference value; wherein the correction factor is used for at least one of adjusting subsequent operation of the impacting device and statistical processing and correction. ### Claim 27 (depends on 20) The method according to claim 20, wherein the monitored displacement of the impacting device is used as input data affecting a feeding rate of viscous medium to the jetting chamber. ### Claim 28 (depends on 20) The method according to claim 20, further comprising the step of calculating at least one presence value based on a comparison between the displacement and a reference displacement value so as to identify the presence of viscous medium in the jetting chamber. ### Claim 29 (depends on 20) The method according to claim 20, wherein the step of monitoring the displacement of the impacting device comprises determining a position of the impacting device at different times during at least one of the forward impact movement of the impacting device and the controlled retraction of the impacting device to the initial position. ### Claim 30 (depends on 20) The method according to claim 20, further comprising a step of identifying a failure mode based on a comparison between the displacement of the impacting device and at least one reference parameter value. ### Claim 31 An ejector for jetting a viscous medium onto a substrate, the ejector comprising: a jetting chamber adapted to accommodate the viscous medium, said jetting chamber comprising an open connection, or inlet, to the channel of the feeder providing the viscous medium to the chamber; a nozzle connected to the chamber; an impacting device adapted to impact a volume of the viscous medium in the chamber such that viscous medium is jetted through the nozzle towards the substrate; and a sensor arranged to output a signal or sensor parameter reflecting a displacement of the impacting device during the impact. ### Claim 32 (depends on 31) The ejector according to claim 31, wherein the sensor is comprised inside the chamber and is arranged for non-contact measurement of at least one of the position (e.g. the end position, or returning position, of the stroke, or forward impact movement), velocity and acceleration of the impacting device. ### Claim 33 (depends on 31) The ejector according to claim 31, wherein the sensor is an optical sensor, a capacitive sensor, a magnetic sensor, a linear variable differential transformer sensor, voice coil or piezoelectric sensor. ### Claim 34 (depends on 31) The ejector according to claim 31, wherein the sensor is a strain sensor. ### Claim 35 (depends on 31) A system for jetting viscous medium onto a substrate, the system comprising: an ejector according to claim 31; and a control unit adapted to control the operation of the impacting device based on the signal or sensor parameter. ### Claim 36 (depends on 35) The system according to claim 35, wherein control unit is adapted to: based on the signal or sensor parameter, determine at least one of a velocity, acceleration, position or length of a stroke of the impacting device during the impact; calculate a correction factor based on a comparison between the determined velocity, acceleration, position and/or length of the stroke and at least one reference value; and use said correction factor for adjusting subsequent operation of the impacting device. ### Claim 37 (depends on 35) The system according to claim 35, wherein the control unit is adapted to: based on the signal or sensor parameter, determine an acceleration of the impacting device during the impact; calculate a correction factor based on a comparison between the determined acceleration and a reference acceleration value; and use said correction factor for adjusting subsequent operation of the impacting device. ### Claim 38 (depends on 35) The system according to claim 35, wherein the control unit is adapted to: based on the signal or sensor parameter, determine, in the time domain, a movement curve for the different positions of the impacting device during the impact; calculate at least one correction factor based on a comparison between the determined movement curve and a reference movement curve; and use said correction factor for adjusting subsequent operation of the impacting device in order to achieve an adjusted movement curve in the time domain for the impacting device.