# US 11,231,392 B2 · Detecting device and method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,231,392 B2 - Document ID: US11231392B2 - Status: Granted - Kind: B2 - Application number: 15/847,599 - Filed: 2017-12-19 - Published: 2018-06-28 - Granted: 2022-01-25 - Earliest claimed: 2016-12-27 - Assignees: Industrial Technology Research Institute - Applicants: Industrial Technology Research Institute - Inventors: Chung-Fan Tu; Hau-Wei Wang - Web page: https://patentgrep.com/patent/US11231392B2 ## CPC - G01N 27/9006: {Details, e.g. in the structure or functioning of sensors} - G01N 27/904: with two or more sensors - G01N 27/9086: {Calibrating of recording device} - G01N 27/9046: {by analysing electrical signals} - 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) ## Abstract A detecting device includes a first coil, a third coil, a second coil, and a fourth coil. The first coil generates a first magnetic field on a to-be-measured object. The third coil generates a third magnetic field under the to-be measured object. The second coil generates a second magnetic field. After the fourth coil receives the second magnetic field, a voltage is induced. The induced voltage is amplified by an amplify circuit to drive the third coil. The directions of the currents generated by the first coil and the third coil, respectively, are the same. ## Claims ### Claim 1 A detecting device, comprising: a first coil set, generating a main magnetic field toward a first side of a to-be-measured object through a main circuit, wherein the to-be-measured object further comprises a second side opposite to the first side; and a second coil set, generating a compensation magnetic field toward the second side of the to-be-measured object through a compensation circuit; wherein a first current generated by the main magnetic field and a second current generated by the compensation magnetic field magnetic field have a same direction; wherein the first coil set forms a positive feedback through an amplifier. ### Claim 2 (depends on 1) The detecting device of claim 1, wherein the main magnetic field and the compensation magnetic field generate a uniform magnetic field. ### Claim 3 (depends on 2) The detecting device of claim 2, wherein the uniform magnetic field passes through the to-be-measured object. ### Claim 4 (depends on 2) The detecting device of claim 2, wherein the uniform magnetic field is perpendicular to the to-be-measured object. ### Claim 5 (depends on 1) The detecting device of claim 1, wherein the amplifier is composed of two amplifiers, and the two amplifiers self-oscillate and provide feedback mutually to form a positive feedback self-oscillation. ### Claim 6 (depends on 1) The detecting device of claim 1, wherein the first coil set and the second coil set generate an alternating magnetic field by the amplifier. ### Claim 7 (depends on 1) The detecting device of claim 1, wherein the compensation circuit is composed of at least one of a current amplifier, a voltage amplifier, and a voltage gain adjuster, wherein an output current of the voltage amplifier drives a change of an alternating current produced by the first coil set and the second coil set which are on and below the to-be-measured object, respectively. ### Claim 8 (depends on 7) The detecting device of claim 7, wherein the voltage amplifier is a multi-stage amplifier. ### Claim 9 (depends on 1) The detecting device of claim 1, wherein an output of the voltage amplifier is converted to a direct current signal and is subtracted from a reference voltage by an amplitude voltage modulator to form a negative feedback. ### Claim 10 (depends on 9) The detecting device of claim 9, wherein the negative feedback controls an amplitude of an oscillation of the first coil to be a constant value. ### Claim 11 (depends on 10) The detecting device of claim 10, wherein the constant value is decided by a value of the reference voltage. ### Claim 12 (depends on 1) The detecting device of claim 1, wherein the first coil set connects to a current sensor in series. ### Claim 13 (depends on 1) The detecting device of claim 1, wherein when an alternating magnetic field of the first coil set passes through the to-be-measured object, and the to-be-measured object induces an eddy current. ### Claim 14 (depends on 13) The detecting device of claim 13, wherein the eddy current generates a second magnetic field. ### Claim 15 (depends on 14) The detecting device of claim 14, wherein the value of the eddy current is changed owing to the second magnetic field is against an alternating magnetic field. ### Claim 16 (depends on 15) The detecting device of claim 15, wherein a change value of the eddy current is converted to a detecting signal by the current sensor. ### Claim 17 (depends on 13) The detecting device of claim 13, wherein a magnitude of the eddy current is relevant to at least one characteristics of the to-be-measured object. ### Claim 18 (depends on 17) The detecting device of claim 17, wherein the at least one characteristics of the to-be-measured object comprises uniformity, conductivity, permeability, defect and thickness. ### Claim 19 (depends on 1) The detecting device of claim 1, wherein the first coil set generates the main magnetic field on the to-be-measured object by an alternating current. ### Claim 20 (depends on 1) The detecting device of claim 1, wherein the second coil set generates the compensation magnetic field below the to-be-measured object by an alternating current. ### Claim 21 (depends on 1) The detecting device of claim 1, wherein a probe of the detecting device and the to-be-measured object have no contact with each other. ### Claim 22 (depends on 1) The detecting device of claim 1, wherein the first coil set and the second coil set are parallel. ### Claim 23 (depends on 1) The detecting device of claim 1, wherein cores of the first coil, the second coil, the third coil, and the fourth coil are in the form of sheets or columnar. ### Claim 24 (depends on 1) The detecting device of claim 1, wherein the main magnetic field and the compensation magnetic field are symmetric. ### Claim 25 (depends on 1) The detecting device of claim 1, wherein the coil of the first coil set and the second coil set are horizontally winding. ### Claim 26 (depends on 1) The detecting device of claim 1, wherein the first coil set and the second coil set have their respective multiple winding coils. ### Claim 27 A detecting method, comprising: providing, by a main circuit, a first alternating current to generate, via a first coil set, a main magnetic field toward a first side of above a to-be-measured object, wherein the to-be-measured object further comprises a second side opposite to the first side; and providing, by a compensation circuit, a second alternating current to generate, via a second coil set, a compensation magnetic field toward the second side of below the to-be-measured object; wherein a first current generated by the main magnetic field and a second current generated by the compensation magnetic field magnetic field have a same direction; wherein the first coil set forms a positive feedback through an amplifier. ### Claim 28 (depends on 27) The detecting method of claim 27, wherein the main magnetic field and the compensation magnetic field generate a uniform magnetic field, and the uniform magnetic field is perpendicular to the to-be-measured object. ### Claim 29 (depends on 27) The detecting method of claim 27, wherein the first coil set generates a first magnetic field. ### Claim 30 (depends on 29) The detecting method of claim 29, wherein the first coil set and the second coil set generate an alternating magnetic field by the amplifier. ### Claim 31 (depends on 29) The detecting method of claim 29, wherein an output of a voltage amplifier is converted to a direct current signal and is subtracted from a reference voltage by an amplitude voltage modulator to form a negative feedback. ### Claim 32 (depends on 31) The detecting method of claim 31, wherein the negative feedback controls an amplitude of an oscillation of the first coil to be a constant value, and the constant value is decided by a value of the reference voltage. ### Claim 33 (depends on 27) The detecting method of claim 27, wherein when an alternating magnetic field of the first coil set passes through the to-be-measured object, the to-be-measured object induces an eddy current, and the eddy current generates a second magnetic field. ### Claim 34 (depends on 33) The detecting method of claim 33, wherein the value of the eddy current is changed owing to the second magnetic field is against an alternating magnetic field. ### Claim 35 (depends on 34) The detecting method of claim 34, wherein a change value of the eddy current is converted to a detecting signal by the current sensor. ### Claim 36 A detecting device, comprising: a first coil, generating a first magnetic field toward a first side of above a to-be-measured object, wherein the to-be-measured object further comprises a second side opposite to the first side; a third coil, generating a third magnetic field toward the second side of below the to-be-measured object; a second coil, generating a second magnetic field; and a fourth coil, wherein a voltage is induced after the fourth coil receives the second magnetic field, and the voltage is amplified by a compensation circuit to drive the third coil; wherein a first current generated by the first magnetic field and a third current generated by the third magnetic field have a same direction; wherein the first coil and the second coil form a positive feedback through an amplifier. ### Claim 37 (depends on 36) The detecting device of claim 36, wherein the first magnetic field and the third magnetic field generate an uniform magnetic field. ### Claim 38 (depends on 37) The detecting device of claim 37, wherein the uniform magnetic field is perpendicular to the to-be-measured object. ### Claim 39 (depends on 37) The detecting device of claim 37, wherein the uniform magnetic field is generated between the first magnetic field and the third magnetic field. ### Claim 40 (depends on 36) The detecting device of claim 36, wherein the amplifier is composed of two amplifiers, and the two amplifiers self-oscillate and provide feedback mutually to form a positive feedback self-oscillation. ### Claim 41 (depends on 36) The detecting device of claim 36, wherein the amplifier drives the first coil and the second coil to generate an alternating magnetic field by the amplifier. ### Claim 42 (depends on 36) The detecting device of claim 36, wherein the compensation circuit is composed of at least one of a current amplifier, a voltage amplifier, a voltage gain adjuster. ### Claim 43 (depends on 42) The detecting device of claim 42, wherein the voltage amplifier is a multi-stage amplifier. ### Claim 44 (depends on 36) The detecting device of claim 36, wherein an output of the voltage amplifier is converted to a direct current signal, and the output is subtracted from a reference voltage by an amplitude voltage modulator to form a negative feedback. ### Claim 45 (depends on 44) The detecting device of claim 44, wherein the negative feedback controls an amplitude of the oscillation of the first coil to be a constant value. ### Claim 46 (depends on 45) The detecting device of claim 45, wherein the constant value is decided by a value of the reference voltage. ### Claim 47 (depends on 36) The detecting device of claim 36, wherein the first coil and the third coil connect to a current sensor in series. ### Claim 48 (depends on 36) The detecting device of claim 36, wherein when an alternating magnetic field between the first coil and the third coil passes through the to-be-measured object, and the to-be-measured object induces an eddy current. ### Claim 49 (depends on 48) The detecting device of claim 48, wherein the eddy current generates the second magnetic field. ### Claim 50 (depends on 49) The detecting device of claim 49, wherein the value of the eddy current is changed owing to the second magnetic field is against an alternating magnetic field. ### Claim 51 (depends on 50) The detecting device of claim 50, wherein a change value of the eddy current is converted to a detecting signal by the current sensor. ### Claim 52 (depends on 48) The detecting device of claim 48, wherein a magnitude of the eddy current is relevant to at least one characteristics of the to-be-measured object. ### Claim 53 (depends on 52) The detecting device of claim 52, wherein the at least one characteristics of the to-be-measured object comprises uniformity, conductivity, permeability, defect and thickness. ### Claim 54 (depends on 36) The detecting device of claim 36, wherein the first coil generates the first magnetic field on the to-be-measured object by an alternating current. ### Claim 55 (depends on 36) The detecting device of claim 36, wherein the third coil generates the third magnetic field below the to-be-measured object by an alternating current. ### Claim 56 (depends on 36) The detecting device of claim 36, wherein a probe of the detecting device and the to-be-measured object have no contact with each other. ### Claim 57 (depends on 36) The detecting device of claim 36, wherein the first coil and the third coil are parallel. ### Claim 58 (depends on 36) The detecting device of claim 36, wherein the second coil and the fourth coil are parallel. ### Claim 59 (depends on 36) The detecting device of claim 36, wherein cores of the first coil, the second coil, the third coil, and the fourth coil are in the form of sheets or columnar. ### Claim 60 (depends on 36) The detecting device of claim 36, wherein the first magnetic field and the third magnetic field are symmetric. ### Claim 61 (depends on 36) The detecting device of claim 36, wherein the first coil, the second coil, the third coil, and the fourth coil are horizontally winding. ### Claim 62 (depends on 36) The detecting device of claim 36, wherein the first coil, the second coil, the third coil, and the fourth coil have their respective multiple winding coils.