DETAILED ACTION
Response to Arguments
Applicant's arguments filed 07/01/2026 have been fully considered but they are not persuasive.
The applicant argues that the prior art does not teach the newly added claim limitations as claimed in claim 1.
This argument is not persuasive because both references teach an excitation mode and a persistent current mode. The current flowing through the coils in each of the two modes is inherently different. Thus, the magnetic field spatial distribution is also different, and changes with the current, since the magnetic field depends on the current in the coils. Specifically, lines 31-55 of column 5 of Yoshikawa, disclose that in the excitation mode the power supply energizes the coils until a current value for the persistent mode is reached. This means that during the excitation mode the spatial distribution of the combined field changes because the field depends on the changing current. In other words, since the persistent current values are different than the excitation mode values, the field values are also different. Thus, a change of spatial distribution of the combined static magnetic field occurs when the mode shifts from excitation mode to the persistent current mode.
Lines 5-25 of column 5 of Shen disclose a similar two mode current application process. Thus, the Shen reference also teaches the claimed change of spatial distribution of the combined static magnetic field, since the spatial distribution of the field is directly dependent on the current in the coils.
Claim Rejections - 35 USC § 103
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, 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.
Claim(s) 1-7, 9-11, and 13-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yoshikawa (US 6646836) in view of Shen et al. (US 6960914).
In re claim 1, Yoshikawa, in figures 1-7, discloses a superconducting magnet comprising: at least one primary superconducting coil (2b) configured to generate a primary static magnetic field by a persistent current flowing during a persistent current mode; at least one secondary superconducting coil (2a) configured to generate a secondary static magnetic field different from the primary static magnetic field in response to external control; and a static-magnetic-field control switch (one of 4 or 5) configured to supply the secondary superconducting coil with part of the persistent current to generate the secondary static magnetic field by being closed (in the on state) in response to the external control during the persistent current mode and stop energization of the secondary superconducting coil and generation of the secondary static magnetic field by being opened in response to the external control during the persistent current mode (inherent functionality of the disclosed structure); wherein the secondary superconducting coil is configured to generate the secondary static magnetic field in such a manner that a spatial distribution of a combined static magnetic field obtained by combining the primary static magnetic field and the secondary static magnetic field changes from the spatial distribution of the combined static magnetic field when a mode shifts from an excitation mode to the persistent current mode (this is inherent because the current is different in each mode, and the field is a product of the current, thus the change in current causes change in field distribution). Yoshikawa does not explicitly teach that the secondary coil cancels or reduces the primary static magnetic field. Shen however, in figures 1-8, teaches a similar device having (a secondary coil (106, 124, 156) used to shield the primary coil by creating an opposing field to the primary coil (shielding involves creating a reverse magnetic field to reduce the magnetic field created by the primary coil, see line 24 of column 1 for description). Therefore it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have configured the secondary coil of Yoshikawa to provide a reverse magnetic field, and thus reduce the primary coil field, as taught by Shen, to provide shielding for the device.
In re claim 2, Yoshikawa, in figures 1-7, discloses that the static-magnetic-field control switch comprises a superconducting member (portion that conducts the superconducting current) and a heater (see lines 55-65 of column 4) configured to heat the superconducting member; the static-magnetic-field control switch is opened when stopping generation of the secondary static magnetic field by turning on the heater under the external control and bringing the superconducting member into a normal conducting state; and the static-magnetic-field control switch is closed when generating the secondary static magnetic field by turning off the heater under the external control and shifting the superconducting member from the normal conducting state to a superconducting state (inherent functionality of the shown structure).
In re claim 3, Yoshikawa/Shen discloses the superconducting member provided in the static magnetic field control switch (as discussed in claims 1-2 above). With respect to the winding process, in accordance to MPEP 2113, the method of forming the device is not germane to the issue of patentability of the device itself. Therefore, this limitation has not been given patentable weight. Please note that even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product, i.e superconducting member, does not depend on its method of production, i.e. winding a superconducting wire. In re Thorpe, 227 USPQ 964, 966 (Federal Circuit 1985).
In re claim 4, Yoshikawa, in figures 1-7, discloses a persistent current switch (one of 4 or 5) configured to: be opened during the excitation mode to allow an electric current supplied from an external power supply to flow through the primary superconducting coil; and be closed during the persistent current mode to form a persistent current loop with the primary superconducting coil in such a manner that the persistent current flows through the primary superconducting coil (inherent function of the shown structure, see lines 30-54 of column 5).
In re claim 5, Yoshikawa, in figures 1-7, discloses that the persistent current switch comprises a superconducting member (portion that conducts the superconducting current) and a heater (see lines 55-65 of column 4) configured to heat the superconducting member; the persistent current switch is opened during the excitation mode by turning on the heater under the external control and bringing the superconducting member into a normal conducting state; and the persistent current switch is closed during the persistent current mode by turning off the heater under the external control and shifting the superconducting member from the normal conducting state to a superconducting state (inherent functionality of the shown structure).
In re claim 6, Yoshikawa in view of Shen, discloses that the secondary superconducting coil is configured to generate the secondary static magnetic field in such a manner that the primary static magnetic field is canceled or reduced (mutual inductance M provides this functionality; coils 123 in figure 2 are also configured to reduce primary static field; Also, Shen explicitly teaches this as discussed in claim 1 rejection).
In re claim 7, Yoshikawa, in view of Shen, discloses that the secondary superconducting coil is configured to generate the secondary static magnetic field due to an emergency magnetic-field shutdown function in such a manner that the primary static magnetic field is canceled by the secondary static magnetic field (the shown structure is configured to and is capable of performing this functionality due to the physical arrangement of the coils shown in the figures).
In re claim 9, Yoshikawa, in figures 1-7, discloses that the secondary superconducting coil is configured as a coil (as seen in the figures). With respect to the winding process, in accordance to MPEP 2113, the method of forming the device is not germane to the issue of patentability of the device itself. Therefore, this limitation has not been given patentable weight. Please note that even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product, i.e coil, does not depend on its method of production, i.e. winding. In re Thorpe, 227 USPQ 964, 966 (Federal Circuit 1985).
In re claim 10, the claim limitations are directed to an external control of the device. It has been held that a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus satisfying the claimed structural limitations. Ex parte Masham, 2 USPQ2d 1647 (1987).
In re claim 11, Yoshikawa, in figures 1-7, discloses that the static-magnetic-field control switch comprises a superconducting member (portion that conducts the superconducting current) and a heater (see lines 55-65 of column 4) configured to heat the superconducting member; the external control is performed in synchronization with a pulse sequence in magnetic resonance imaging (it is inherent to an MRI device that imaging pulse sequence is synchronized with magnet control in order for proper imaging functionality); and a timing of the external control is determined in consideration of a delay time from turning on or off the heater until the static-magnetic-field control switch closes or opens, with respect to a change timing of the primary static magnetic field in the pulse sequence, or the combined static magnetic field obtained by combining the primary static magnetic field and the secondary static magnetic field (lines 45-54 of column 5 discuss timing of external control in consideration of a combined static field (achieved in persistent current state)).
In re claim 13, Yoshikawa, in figures 1-7, discloses an MRI apparatus.
In re claim 14, Yoshikawa in view of Shen discloses that the static-magnetic-field control switch is configured to be controlled in response to the external control after reaching the persistent current mode (this is an inherent functionality of the shown device; control and monitoring is required to operate the device in all current modes).
In re claim 15, Yoshikawa in view of Shen discloses that the at least one primary superconducting coil is connected in parallel to the at least one secondary superconducting coil (this is true in Yoshikawa device in the persistent current mode condition when the current supply is turned off; both ends of the coils are connected together thereby forming a parallel connection; Shen shows the same connection).
In re claim 16, Yoshikawa in view of Shen discloses that the at least one primary superconducting coil and the at least one secondary superconducting coil are connected in series (this is true in Yoshikawa device when the current source is connected to the coils; Shen shows the same connection), and the at least one secondary superconducting coil is wound with a winding pattern that cancels the primary magnetic field generated (Shen teaches reducing the field, which is inherently canceled at some positions between the coils due to the secondary coil producing the opposing field), and the part of the persistent current flows when the static-magnetic-field control switch is opened (in the same way as disclosed by the applicant).
Conclusion
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/Alexander Talpalatski/Primary Examiner, Art Unit 2837
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