# US 10,120,448 B2 · Method of tuning a haptic actuator including ferromagnetic mass change iterations and related apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,120,448 B2 - Document ID: US10120448B2 - Status: Granted - Kind: B2 - Application number: 14/819,910 - Filed: 2015-08-06 - Published: 2017-02-09 - Granted: 2018-11-06 - Earliest claimed: 2015-08-06 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Arman Hajati - Web page: https://patentgrep.com/patent/US10120448B2 ## CPC - G06F 3/016: {Input arrangements with force or tactile feedback as computer generated output to the user} - G04C 3/004: {Magnetically controlled} - G04G 21/00: Input or output devices integrated in time-pieces - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G04C: ELECTROMECHANICAL CLOCKS OR WATCHES - G04G: ELECTRONIC TIME-PIECES ## Abstract A method is directed to tuning a haptic actuator that includes a housing having a ferromagnetic mass, a coil carried by the housing, and a field member movable within the housing responsive to the coil. The haptic actuator is operative as a resonator and has an initial quality (Q) factor. The method may include determining whether the initial Q factor is within a desired Q factor range, and when the initial Q factor is not within the desired Q factor range, performing ferromagnetic mass change iterations until an updated Q factor is within the desired Q factor range. Each ferromagnetic mass change iteration may include changing the ferromagnetic mass of the housing, determining the updated Q factor based upon changing the ferromagnetic mass of the housing, and determining whether the updated Q factor is within the desired Q factor range. Another embodiment changes the ferromagnetic mass of the field member. ## Claims ### Claim 1 A method of tuning a haptic actuator comprising a housing having a ferromagnetic mass, at least one coil carried by the housing, and a field member movable within the housing responsive to the at least one coil, the haptic actuator operative as a resonator and having an initial quality (Q) factor, the method comprising: determining whether the initial Q factor is within a desired Q factor range; and when the initial Q factor is not within the desired Q factor range, performing at least one ferromagnetic mass change iteration until an updated Q factor is within the desired Q factor range, the at least one ferromagnetic mass change iteration comprising changing, using a mass changing device, the ferromagnetic mass of the housing, determining the updated Q factor of the haptic actuator based upon changing the ferromagnetic mass of the housing, and determining whether the updated Q factor is within the desired Q factor range. ### Claim 2 (depends on 1) The method of claim 1 wherein changing the ferromagnetic mass of the housing comprises adding ferromagnetic mass to the housing. ### Claim 3 (depends on 1) The method of claim 1 wherein changing the ferromagnetic mass of the housing comprises removing ferromagnetic mass from the housing. ### Claim 4 (depends on 3) The method of claim 3 wherein removing ferromagnetic mass from the housing comprises laser ablating ferromagnetic mass from the housing. ### Claim 5 (depends on 1) The method of claim 1 wherein changing the ferromagnetic mass of the housing comprises adding a ferromagnetic body to the housing. ### Claim 6 (depends on 1) The method of claim 1 wherein the desired Q factor range is between 8 and 15. ### Claim 7 (depends on 1) The method of claim 1 wherein the housing has a top and a bottom; and wherein changing the ferromagnetic mass of the housing comprises changing the ferromagnetic mass of one of the top and bottom of the housing. ### Claim 8 (depends on 1) The method of claim 1 wherein the field member comprises at least one permanent magnet and at least one mass coupled thereto. ### Claim 9 A method of tuning a haptic actuator comprising a housing, at least one coil carried by the housing, and a field member movable within the housing responsive to the at least one coil and having a ferromagnetic mass, the haptic actuator operative as a resonator and having an initial quality (Q) factor, the method comprising: determining whether the initial Q factor is within a desired Q factor range; and when the initial Q factor is not within the desired Q factor range, performing at least one ferromagnetic mass change iteration until an updated Q factor is within the desired Q factor range, the at least one ferromagnetic mass change iteration comprising changing, using a mass changing device, the ferromagnetic mass of the field member, determining the updated Q factor of the haptic actuator based upon changing the ferromagnetic mass of the field member, and determining whether the updated Q factor is within the desired Q factor range. ### Claim 10 (depends on 9) The method of claim 9 wherein changing the ferromagnetic mass of the field member comprises adding ferromagnetic mass to the field member. ### Claim 11 (depends on 9) The method of claim 9 wherein changing the ferromagnetic mass of the field member comprises removing ferromagnetic mass from the field member. ### Claim 12 (depends on 11) The method of claim 11 wherein removing ferromagnetic mass from the field member comprises laser ablating ferromagnetic mass from the field member. ### Claim 13 (depends on 9) The method of claim 9 wherein changing the initial ferromagnetic mass of the field member comprises adding a ferromagnetic body to the field member. ### Claim 14 (depends on 9) The method of claim 9 wherein the desired Q factor range is between 8 and 15. ### Claim 15 An apparatus for tuning a haptic actuator comprising a housing having an initial ferromagnetic mass, at least one coil carried by the housing, and a field member movable within the housing responsive to the at least one coil, the haptic actuator operative as a resonator and having an initial quality (Q) factor, the apparatus comprising: at least one sensor; a mass changing device; and a controller capable of cooperating with the at least one sensor to determine whether the initial Q factor is within a desired Q factor range, and when the initial Q factor is not within the desired Q factor range, performing at least one ferromagnetic mass change iteration until an updated Q factor is within the desired Q factor range, the at least one ferromagnetic mass change iteration comprising cooperating with the mass changing device to change the ferromagnetic mass of the housing, cooperating with the at least one sensor to determine the updated Q factor of the haptic actuator based upon changing the ferromagnetic mass of the housing, and determining whether the updated Q factor is within the desired Q factor range. ### Claim 16 (depends on 15) The apparatus of claim 15 wherein the mass changing device is capable of changing the ferromagnetic mass of the housing by adding ferromagnetic mass to the housing. ### Claim 17 (depends on 15) The apparatus of claim 15 wherein the mass changing device is capable of changing the ferromagnetic mass of the housing by removing ferromagnetic mass from the housing. ### Claim 18 (depends on 17) The apparatus of claim 17 wherein the mass changing device is capable of removing ferromagnetic mass from the housing by laser ablating ferromagnetic mass from the housing. ### Claim 19 (depends on 15) The apparatus of claim 15 wherein the mass changing device is capable of changing the ferromagnetic mass of the housing by adding a ferromagnetic body to the housing. ### Claim 20 (depends on 15) The apparatus of claim 15 wherein the mass changing device is capable of changing the ferromagnetic mass of the housing to the desired ferromagnetic mass so that the desired Q factor is in a range between 8 and 15. ### Claim 21 An apparatus for tuning a haptic actuator comprising a housing having an initial ferromagnetic mass, at least one coil carried by the housing, and a field member movable within the housing responsive to the at least one coil, the haptic actuator operative as a resonator and having an initial quality (Q) factor, the apparatus comprising: at least one sensor; a mass changing device; and a controller capable of cooperating with the at least one sensor to determine whether the initial Q factor is within a desired Q factor range, and when the initial Q factor is not within the desired Q factor range, performing at least one ferromagnetic mass change iteration until an updated Q factor is within the desired Q factor range, the at least one ferromagnetic mass change iteration comprising cooperating with the mass changing device to change the ferromagnetic mass of the field member, cooperating with the at least one sensor to determine the updated Q factor of the haptic actuator based upon changing the ferromagnetic mass of the field member, and determining whether the updated Q factor is within the desired Q factor range. ### Claim 22 (depends on 21) The apparatus of claim 21 wherein the mass changing device is capable of changing the ferromagnetic mass of the field member by adding ferromagnetic mass to the field member. ### Claim 23 (depends on 21) The apparatus of claim 21 wherein the mass changing device is capable of changing the ferromagnetic mass of the field member by removing ferromagnetic mass from the field member. ### Claim 24 (depends on 23) The apparatus of claim 23 wherein the mass changing device is capable of removing ferromagnetic mass from the housing by laser ablating ferromagnetic mass from the housing. ### Claim 25 (depends on 21) The apparatus of claim 21 wherein the mass changing device is capable of changing the ferromagnetic mass of the field member by adding a ferromagnetic body to the field member. ### Claim 26 (depends on 21) The apparatus of claim 21 wherein the mass changing device is capable of changing the ferromagnetic mass of the field member to the desired ferromagnetic mass so that the desired Q factor is in a range between 8 and 15.