Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after allowance or after an Office action under Ex Parte Quayle, 25 USPQ 74, 453 O.G. 213 (Comm'r Pat. 1935). Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, prosecution in this application has been reopened pursuant to 37 CFR 1.114. Applicant's submission filed on 02/09/2026 has been entered.
Response to Arguments
Applicant's arguments filed 02/09/2026 have been fully considered but they are not persuasive.
Applicant argues that Snoeij drives the excitation coil using current pulses while the compensation coil current is proportional to the sensed magnetic field, and therefore Snoeij does not teach selecting a current corresponding to a state of a set of discreate states, and Schaffer also discloses excitation current pulses and therefore would not remedy the alleged deficiency of Snoeij.
Examiner respectfully disagrees, Snoeij discloses a fluxgate magnetic sensing circuit including excitation, sensing and compensation coils in which a sensed voltage across the sense coil is processed by a readout circuit and integrator to generate a compensation coil that produces an opposing magnetic field [0025-29], teaching coil current being controlled based on signals derived from the sensed magnetic field within a fluxgate feedback system. Schaffer teaches a fluxgate excitation circuit including a pulsed current source in which control signals select among discrete current levels applied to a coil through switching elements [0006, 0019-22]. Accordingly, teaches selecting among discrete current levels responsive to control states.
Applicant further argues Schaffer does not disclose compensation coil. However, the secondary reference needs to disclose the identical coil being modified. Schaffer teaches discrete current level control for driving a coil in a fluxgate sensor. A person of ordinary skill in the art would recognize that such current control techniques can be applied to other coil driving circuits within similar magnetic systems, including the compensation coil control circuitry of Snoeij.
Applicant further argues that the excitation coil and compensation coil in Snoeij operate differently and therefore would not achieve similar benefits when driven similarly.
Examiner respectfully disagrees because the proposed modification concerns the technique used to control current supplied to a coil rather than the function of the coil itself. The rejection relies on Schaffer for the teaching of discrete current control, not the functional role of the coil. Applying a known current control technique to another coil within the fluxgate sensor system would have been within the level of ordinary skill in the art.
Applicant further asserts that proposed combination relies on impermissible hindsight.
Examiner respectfully disagrees, the combination relies on explicit t teachings from the prior art regarding fluxgate sensor architecture [0025-29] and discrete current control techniques for coil excitation [0006, 0019-22]. Applying a known current control technique from one fluxgate circuit to another similar magnetic sensing circuit would have been within the level of ordinary skill in the art and represents no more than the predictable application of a known technique.
Applicants’ arguments regarding claims 20, 24 including providing a signal representing a threshold filed strength level from a set of discrete strength levels to a coil that generates a magnetic field that at least partially compensate another magnetic field.
Examiner respectfully disagrees as Snoeij teaches generating a compensation magnetic field through a coil responsive to signals derived from the sensed magnetic field in a fluxgate sensing system [0027-29]. Schaffer teaches controlling current supplied to a coil selectable discrete current levels responsive to control signals [0006, 0019-22]. The combination therefore suggests providing selectable current levels to a coil to generate corresponding magnetic field levels within a fluxgate sensing system. Selecting among discrete current levels to generate corresponding magnetic field levels represents the application of a know current control technique to the fluxgate sensing architecture disclosed by Snoeij.
Claim Rejections - 35 USC § 103
4. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-3, 5-27 are rejected under 35 U.S.C. 103 as being unpatentable over Snoeij (U.S. Publication 20160334473) in view of Schaffer (U.S. Publication 20150048818).
Regarding claim 1, Snoeij discloses an apparatus (fig.1 (100)) comprising:
a first coil (fig.1 (105));
a second coil (fig.1 (104))
a control circuit (fig.1 (108 and 109)) having a control input (fig.1 (input to 108)) and a
Snoeij does not explicitly teach responsive to the control input being in a state of a set of discrete states, select, from a set of currents corresponding to the set of discrete states, a current corresponding to the state of the control input and set the current through the first coil.
However, Schaffer in a relevant art teaches an excitation control circuit for fluxgate sensor in which control input selects between first and second discrete current levels applied to excitation coil through controlled switching elements Q1-4 teaching responsive to the control input being in a state of a set of discrete states, select, from a set of currents corresponding to the set of discrete states, a current corresponding to the state of the control input and set the current through the first coil (an excitation control circuit for a fluxgate sensor in which control input signals select among discrete current levels applied to a coil through controller switching elements (Q1-Q4) [0006, 0019-22] In Schaffer, the control signals determine which switching elements conduct, thereby selecting between different current levels supplied by the pulsed current source to the excitation coil. ).
It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention to incorporate Schaffer’s discrete state current control technique into the coil driving circuitry of Snorij in order to provide selectable current levels for controlling the magnetic field generated by the coil within the fluxgate sensing system. Applying a known current control technique to regulate coil current in a similar magnetic sensing system represents the predictable use of prior art elements according to their established functions [0002]
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Regarding claim 2, Snoeij as modified further teaches a core (fig. 1 102) surrounded by the first and second coils (fig. 1 104, 105 around 102).
Regarding claims 3, 26, Snoeij as modified further teaches the first coil is configurable configurable
Regarding claim 5, Snoeij as modified further teaches wherein the control circuit has a control output (fig. 1 (output of 108, 109)), and the control circuit is configurable to set the current to a value representing a field strength level of a set of discrete field strength levels responsive to the state of the control input, and the state of the control input represents a relationship between a strength of the external magnetic field and the set of discrete field strength levels (the output of 108, 109 is set based on the combined fields, 203, 204 added/ subtracted from external magnetic field and the net change in flux induces a voltage (V.sub.sense) across sense coil 104 [0027-0028] ).
Regarding claim 6, Snoeij as modified further teaches wherein the control circuit is configurable to set the control output to a first state responsive to the state of the control input fig. 1 (output of 108, 109 as per the input to 108 from 107)) representing that the combined magnetic field has an opposite polarity to the external magnetic field (“The integrator output connects to a differential driver 109 that outputs a compensation current through compensation coil 105. The compensation coil 105 generates [[an]] the opposing magnetic field (−B) that brings the overall magnetic field at sense coil 104 back to zero” [0028]).
Regarding claim 7, Snoeij as modified further teaches wherein the control output having the first state represents that the strength of the external magnetic field is below the
Regarding claim 8, Snoeij as modified further teaches wherein the control circuit is configurable to set the control output to a second state responsive to the state of the control input representing that the external magnetic field saturates a region surrounded by the first and second coils, and if the compensation magnetic field has a zero strength (“This voltage (Vsense) is detected by fluxgate readout circuit 107, which in turn applies a proportional DC voltage to integrator 108. The integrator output connects to a differential driver 109 that outputs a compensation current through compensation coil 105. The compensation coil 105 generates an opposing magnetic field (−B) that brings the overall magnetic field at sense coil 104 back to zero” [0028]).
Regarding claim 9, Snoeij as modified further teaches wherein value is a first value, the field strength level is a first field strength level, the compensation magnetic field is a first compensation magnetic field (fig. 1 (output of 105)), the combined magnetic field is a first combined magnetic field (fig. 1 (output of 104 sensed on 107)), and the control circuit is configurable to, responsive to the state of the control input indicating that the first combined magnetic field has a same polarity as the external magnetic field (fig. 1 output of 108, 109, when no external magnetic field [0026]): a second field strength level of the set of discrete field strength levels (output of 108, 109 in the presence of magnetic field [0027-0028]), the second field strength level being higher than the first field strength level (field is higher in the presence of external magnetic field [0027]); wherein the first coil is configurable to generate a second compensation magnetic field responsive to the current having the second value; and wherein the second coil is configurable to generate the signal responsive to a second combined magnetic field, the second combined magnetic field being a combination of the external magnetic field and the second compensation magnetic field (“when an external field B is present (i.e., when |B|>0), the flux induced across core rods 201, 202 will not cancel out. Instead, core 201, which is generating field 203 in the direction of the external field, will go into saturation sooner (i.e., field 203 adds to B). Meanwhile, core 202, which is generating field 204 opposite the external field, goes into saturation later (i.e., field 204 subtracts from B). Because of this effect, the flux generated by the excitation current across core rods 201, 202 does not exactly cancel out. This results in a net change in flux across sense coil 104 with each pulse of the excitation current. According to Faraday's law, this net change in flux induces a voltage (V.sub.sense) across sense coil 104” [0027-0028]).
Regarding claim 10, Snoeij as modified further teaches wherein the control circuit is configurable to set the control output to a second state responsive to the state of the control input representing that the second combined magnetic field has a same polarity as the external magnetic field (“This voltage (Vsense) is detected by fluxgate readout circuit 107, which in turn applies a proportional DC voltage to integrator 108. The integrator output connects to a differential driver 109 that outputs a compensation current through compensation coil 105. The compensation coil 105 generates an opposing magnetic field (−B) that brings the overall magnetic field at sense coil 104 back to zero” [0028]).
Regarding claim 11, Snoeij as modified further teaches wherein the control output having the second state represents that the strength of the external magnetic field is above the second field strength level (in the presence or external magnetic field the second filed will be higher vs no external magnetic field [0026-0027]).
Regarding claim 12, Snoeij as modified further teaches wherein the control output has one of the first state or a second state before the control circuit provides the current having the second value; and wherein the control circuit is configurable to set the control output to the one of the first state or the second state responsive to the state of the control input representing that the second combined magnetic field has an opposite polarity to the external magnetic field (fig. 1 the output of integrator 108 and differential driver 109 are controlled as per the input from 107 and are configured to change [0027-0028]).
Regarding claim 13, Snoeij as modified further teaches a third coil (fig. 1 (103))configurable to provide an excitation signal at the excitation output (fig. 1 (106)).
Regarding claim 14, Snoeij as modified further teaches the field strength level is a first field strength level; in a first measurement cycle: the excitation circuit is configurable to provide a first pulse as the excitation signal at the excitation output; the control circuit is configurable to provide
Regarding claim 15, Snoeij as modified further teaches wherein the excitation circuit is configurable to provide a third pulse and the first pulse in the first measurement cycle, and provide a fourth pulse and the second pulse in the second measurement cycle; and wherein the first and third pulses have opposite polarities, and the second and fourth pulses have opposite polarities (fig. 4 (excitation cycles 401,405,414, 412, 409, 405)).
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Regarding claim 16, Snoeij as modified further teaches wherein the first and second coils are encapsulated in a magnetic molding compound (fig. 7 (701)” Fluxgate Sensor 701 has a single magnetic core 702 wrapped by two coils 703, 704” inherently encapsulated [0040]).
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Regarding claim 17, Snoeij as modified further teaches wherein the processing circuit includes: an integrator having integrator inputs and integrator outputs, the integrator inputs coupled to the processing inputs (fig. 1 108 getting inputs from 107); and a comparator having comparator inputs and a comparator output, the comparator inputs coupled to the integrator outputs, and the comparator output coupled to the second output (“a demodulator switch receiving an output from the voltage-to-current converter and generating current signal, a capacitor coupled to the output of the demodulator switch, and a comparator coupled to the capacitor and to a reference voltage, the comparator outputting a signal indicating detection of voltage pulses on the core rod” [0009]).
Regarding claim 18, the structure recited is intrinsic to the method recited in claim 7, as disclosed by Snoeij (U.S. Publication 20160334473) in view of Schaffer (U.S. Publication 20150048818) as the recited structure will be used during the normal operation, as discussed above with regard to claim 1. Snoeij further discloses a compensation magnetic field control output (“The integrator output connects to a differential driver 109 that outputs a compensation current through compensation coil 105. The compensation coil 105 generates an opposing magnetic field (−B) that brings the overall magnetic field at sense coil 104 back to zero [0028]), first signal,…,at the compensation magnetic field control output (signal output from integrator to compensation coil carry the field information from 107 fig. 1 [0026-0027]).
Regarding claims 19, 25, Snoeij as modified further teaches a first coil coupled to the compensation magnetic field control output (fig. 1 via 105); and a second coil coupled to the magnetic field sensing input (fig. 1 104 to 107), and the second coil configurable to sense the magnetic field in a region surrounded by the first and second coils (field sensed by 104 fig. 1).
Regarding claim 20, the method recited is intrinsic to the apparatus recited in claim 1, as disclosed by Snoeij (U.S. Publication 20160334473) in view of Schaffer (U.S. Publication 20150048818) as the recited method steps will be performed during the normal operation of the apparatus, as discussed above with regard to claim 1. Snoeji further discloses first signal represents at least one of: a polarity of a first magnetic field (the output of 108, 109 is set based on the combined fields, 203, 204 added/ subtracted from external magnetic field and the net change in flux induces a voltage (V.sub.sense) across sense coil 104 [0027-0028], in the presence of external field and the combined field and external magnetic field change in flux sensed on 104 which gives same polarity output to 108 [0027]), after providing the second signal, receiving a second one of the first signal representing a polarity of a hird magnetic field from the first coil; and responsive to the polarity of the third magnetic field (net change in flux across sense coil 104 detected by readout circuit 107 [0027-28, 33] fig. 4 excitation cycles 401,405,414,412,409 and 405 showing field strength behavior in the presence and absence of external, magnetic field further [040-45] teaches feedback from the sense circuit used to control excitation pulses that establish a target magnetic flux density in the core) providing a third signal representing whether a strength of the first magnetic field exceeds the threshold field strength level (fig. 4 different excitation cycles excitation cycles 401,405,414, 412, 409, 405 showing field strength with the presence and absence of external magnetic field) further [0040-45] teaches feedback from sense circuit to control excitation pulses that establish a target (threshold) magnetic flux density in the core).
Regarding claim 21, Snoeij as modified further teaches wherein the first one of the first signal indicates at least one of: the first magnetic field does not saturate the region, or a polarity of the first magnetic field (“the excitation current applied to the excitation coil causes V.sub.S-half pulses 602 to be detected across half sense coil 501. These pulses alternate polarity as the rod core is driven into and out of saturation by the excitation current applied to excitation coil” [0036]).
Regarding claim 22, Snoeij as modified further teaches wherein the second signal causes the second coil to generate the second magnetic field having an opposite polarity to the first magnetic field and having the threshold field strength level (further [0040-45] teaches feedback from sense circuit to control excitation pulses that establish a target (threshold) magnetic flux density in the core); and wherein the third magnetic field is a combination of the first and second magnetic fields (“Core 102 is set up to measure a magnetic field in the direction of B” when an external field B is present, the flux induced across core rods 201, 202 will not cancel out. Instead, core 201, which is generating field 203 in the direction of the external field, will go into saturation sooner (i.e., field 203 adds to B). Meanwhile, core 202, which is generating field 204 opposite the external field, goes into saturation later (i.e., field 204 subtracts from B). Because of this effect, the flux generated by the excitation current across core rods 201, 202 does not exactly cancel out [0027], “his voltage (Vsense) is detected by fluxgate readout circuit 107, which in turn applies a proportional DC voltage to integrator 108. The integrator output connects to a differential driver 109 that outputs a compensation current through compensation coil 105. The compensation coil 105 generates an opposing magnetic field (−B) that brings the overall magnetic field at sense coil 104” [0027-28]).
Regarding claim 23, Snoeij as modified further teaches responsive to the polarity of the third magnetic field, providing a second one of the second signal representing second field strength level to the second coil (fig. 4 (vs1 on different excitation levels between field on no field cases) [0027-28]); and after providing the second one of the second signal, receiving a third one of the first signal representing a polarity of a fourth magnetic field from the first coil; and responsive to the polarity of the fourth magnetic field, providing the third signal representing whether a strength of the first magnetic field exceeds the second field strength level (fig. 4 (vs2, vsense on different excitation levels between field on no field cases) “hen an external field (B) is present (403), the flux generated by the excitation current (I.sub.excitation) 401 across each half of sense coil 104 does not cancel out. On positive pulses 409, sense-coil portion 104A saturates faster than sense-coil portion 104B. As a result, voltage pulses V.sub.S1 410 across sense-coil portion 104A are shorter than voltage pulses V.sub.S2 411 across sense-coil portion 104B. The opposite effect occurs for negative pulses 412. Due to the difference in pulse length, the sense-coil voltages (V.sub.S1 410, V.sub.S2 411) do not cancel each other out. Therefore, in the presence of an external field (B) the output (Vs) of the sense coil 104 comprises a series of pulses 413 that are caused by the external field (B)” [0033] field will be higher when external magnetic field is present).
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Regarding claim 24, the structure recited is intrinsic to the method recited in claim 20, as disclosed by Snoeij (U.S. Publication 20160334473) in view of Schaffer (U.S. Publication 20150048818) as the recited structure will be used during the normal operation of the method, as discussed above with regard to claim 20. Snoeij further discloses magnetic field sensing input (fig. 1 104 to 107).
Regarding claim 27, Snoeij does not explicitly teach a set of discrete strength levels.
However, Schaffer in a relevant art teaches an excitation control circuit for fluxgate sensor in which control input selects between first and second discrete current levels applied to excitation coil through controlled switching elements Q1-4 teaching a set of discrete strength levels (control input signals 22 that select among first and second current levels (discrete states) applied through the excitation coil ([0006, 0019-0022])).
It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention to incorporate Schaffer’s discrete state current control technique into the excitation control circuit of Snoeij to improve control precision and enable digital programmability of excitation current levels without changing the fundamental operation of magnetic sensing apparatus [Schaffer’s [0002]].
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Huber (U.S. Publication 20190107585) discloses MAGNETIC SENSOR SENSITIVITY MATCHING CALIBRATION
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/TAQI R NASIR/Examiner, Art Unit 2858
/LEE E RODAK/Supervisory Patent Examiner, Art Unit 2858