DETAILED ACTION
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 .
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claims 1, 11 and 13-20 are rejected under 35 U.S.C. 103 as being unpatentable over Lemaitre (US 2017/0250051 A1) in view of Canfield (US 2016/0217965 A1).
Regarding claim 1, Lemaitre discloses a cathode assembly (Figs.2-9), including:
a) a cathode, including at least two emission portions 55, each of which is configured to independently emit an electron beam (pars.0038-0039), the at least two emission portions 55 being arranged around a center of the cathode (Figs.4 and 5);
b) a focusing electrode 306, the focusing electrode 306 being arranged around a periphery of the cathode; and
c) an auxiliary electrode 308, the auxiliary electrode being arranged within a fitting hole surrounded by the at least two emission portions (Figs.4 and 5; if the two long, rectangular emission portions in Figs.5 and 12 of Applicant’s specification may be considered to be surrounding the fitting hole, then so do the flat emitters of Lemaitre), an insulating layer 1002 being provided between the auxiliary electrode and the at least two emission portions 55 (Fig.9).
Further regarding claim 1, Lemaitre does not specifically disclose that a first surface of the focusing electrode forms an acute angle with an axial direction passing through the center of the cathode. The side view of Fig.2 suggests an acute angle; however, there is no clear disclosure. Lemaitre does state that the at least two emitting portions 55 may be at an angle of 5 to 25 degrees from the plane of the cathode (65 to 85 degrees from the axial direction) in order to optimize the focus of the electron beam emitted from each emitter 55 (par.0040).
Canfield teaches the practice of having a multi-emitter cathode where the surface of the focusing electrode 212, 716 is oriented at substantially the same acute angle from the axial direction as the angle at which the emitters are arranged (Figs.3A-C vs. 7A-B) in order to maintain optimal focus of the emitted electron beams (par.0063).
It would have been obvious to one of ordinary skill in the art at the time of the invention for Lemaitre to have the focusing electrode form an acute angle with the axial direction passing through the center of the cathode, as implied by Lemaitre, in order to ensure optimal focus of the electron beams emitted from the at least two emitting portions, as taught by Canfield.
With respect to claim 11, Lemaitre further discloses that the focusing electrode 306 includes at least two focusing poles, the at least two focusing poles being arranged in a one-to-one correspondence with the at least two emission portions 55 (Figs.4 and 5).
With respect to claim 13, Lemaitre further discloses that adjacent edges of any two adjacent emission portions 55 of the at least two emission portions 55 are parallel (Fig.4).
Regarding claim 14, Lemaitre discloses a method for adjusting a focal point of an x-ray using a cathode assembly;
where the cathode includes:
a) a cathode, including at least two emission portions 55, each of which is configured to independently emit an electron beam (pars.0038-0039), the at least two emission portions 55 being arranged around a center of the cathode (Figs.4 and 5);
b) a focusing electrode 306, the focusing electrode 306 being arranged around a periphery of the cathode; and
c) an auxiliary electrode 308, the auxiliary electrode being arranged within a fitting hole surrounded by the at least two emission portions (Figs.4 and 5; if the two long, rectangular emission portions in Figs.5 and 12 of Applicant’s specification may be considered to be surrounding the fitting hole, then so do the flat emitters of Lemaitre), an insulating layer 1002 being provided between the auxiliary electrode and the at least two emission portions 55 (Fig.9);
where the method includes:
d) obtaining an operating mode of an x-ray tube (from operator, par.0033);
e) applying a preset current to the cathode according to the operating mode, to selectively control one or more of the at least two emission portions 55 of the cathode to emit the electron beams (par.0034 for electrical connections; par.0039 for selective emission from one or both emitters 55 to achieve the desired focal spot size).
Further regarding claim 14, Lemaitre does not specifically disclose that a first surface of the focusing electrode forms an acute angle with an axial direction passing through the center of the cathode. The side view of Fig.2 suggests an acute angle; however, there is no clear disclosure. Lemaitre does state that the at least two emitting portions 55 may be at an angle of 5 to 25 degrees from the plane of the cathode (65 to 85 degrees from the axial direction) in order to optimize the focus of the electron beam emitted from each emitter 55 (par.0040).
Canfield teaches the practice of having a multi-emitter cathode where the surface of the focusing electrode 212, 716 is oriented at substantially the same acute angle from the axial direction as the angle at which the emitters are arranged (Figs.3A-C vs. 7A-B) in order to maintain optimal focus of the emitted electron beams (par.0063).
It would have been obvious to one of ordinary skill in the art at the time of the invention for Lemaitre to have the focusing electrode form an acute angle with the axial direction passing through the center of the cathode, as implied by Lemaitre, in order to ensure optimal focus of the electron beams emitted from the at least two emitting portions, as taught by Canfield.
Regarding claim 15, Lemaitre discloses a method for controlling a focused electron beam using a cathode assembly;
where the cathode assembly includes:
a) a cathode, including at least two emission portions 55, each of which is configured to independently emit an electron beam (pars.0038-0039), the at least two emission portions 55 being arranged around a center of the cathode (Figs.4 and 5);
b) a focusing electrode 306, the focusing electrode 306 being arranged around a periphery of the cathode; and
c) an auxiliary electrode 308, the auxiliary electrode being arranged within a fitting hole surrounded by the at least two emission portions (Figs.4 and 5; if the two long, rectangular emission portions in Figs.5 and 12 of Applicant’s specification may be considered to be surrounding the fitting hole, then so do the flat emitters of Lemaitre), an insulating layer 1002 being provided between the auxiliary electrode and the at least two emission portions 55 (Fig.9);
where the method includes:
d) determining at least one target emission portion of the cathode according a desired position and a desired size of a target focal point (selective operation of one or both emitters 55, par.0039);
e) providing a first potential to the at least one target emission portion (first sentence of par.0039); and
f) providing a second potential to the focusing electrode 306 so as to focus the electron beam emitted from the at least one target emission portion 55 (pars.0041-0042).
Further regarding claim 15, Lemaitre does not specifically disclose that a first surface of the focusing electrode forms an acute angle with an axial direction passing through the center of the cathode. The side view of Fig.2 suggests an acute angle; however, there is no clear disclosure. Lemaitre does state that the at least two emitting portions 55 may be at an angle of 5 to 25 degrees from the plane of the cathode (65 to 85 degrees from the axial direction) in order to optimize the focus of the electron beam emitted from each emitter 55 (par.0040).
Canfield teaches the practice of having a multi-emitter cathode where the surface of the focusing electrode 212, 716 is oriented at substantially the same acute angle from the axial direction as the angle at which the emitters are arranged (Figs.3A-C vs. 7A-B) in order to maintain optimal focus of the emitted electron beams (par.0063).
It would have been obvious to one of ordinary skill in the art at the time of the invention for Lemaitre to have the focusing electrode form an acute angle with the axial direction passing through the center of the cathode, as implied by Lemaitre, in order to ensure optimal focus of the electron beams emitted from the at least two emitting portions, as taught by Canfield.
With respect to claim 16, Lemaitre further discloses that the focusing electrode 306 includes at least two focusing electrode poles 306, the at least two focusing poles 306 being arranged in a one-to-one correspondence with the at least two emission portions 55 (Fig.4); where the step of providing a second potential to the focusing electrode 306 includes providing the second potential to the focusing pole 306 corresponding to the at least one target emission portion 55 (par.0040).
With respect to claim 17, Lemaitre further discloses providing a third potential to the auxiliary electrode (par.0046).
With respect to claim 18, Lemaitre further discloses that, after providing a third potential to the auxiliary electrode 308, the method further includes adjusting a difference between the second potential of the focusing pole 306 corresponding to the at least one target emission portion 55 and the third potential of the auxiliary electrode 308 so as to move the electron beam emitted from the at least one target emission portion 55 (par.0046).
With respect to claim 19, Lemaitre does not specifically disclose periodically changing a difference between the second potential and the third potential. Lemaitre does state that the difference between the second potential applied to the focusing pole 306 corresponding to the target emission portion 55 and the third potential applied to the auxiliary electrode 308 enables the tube to shift the focal spot position as desired (par.0046).
The skilled artisan readily appreciates the fact that it is well known to periodically shift the focal spot position, either for (i) real-time feedback stability control, (ii) performing a focal spot wobble for enhancing spatial resolution in CT image acquisition, (iii) switching the focal spot between two or more target compositions on the anode target for interleaved dual-energy or multi-energy image acquisition, and/or (iv) acquiring stereo images from a single x-ray tube by taking alternate images from different focal spot positions.
It would have been obvious to one of ordinary skill in the art at the time of the invention for Lemaitre to periodically change the difference between the second potential applied to the corresponding focusing pole and the third potential applied to the auxiliary electrode in order to achieve any of the identified improvements and/or imaging mode enhancements as are all well known in the art.
With respect to claim 20, Lemaitre further discloses:
g) adjusting the third potential to be within a first preset range (par.0046);
h) adjusting the second potential of the focusing pole 306 corresponding to one or more of the at least two target emission portions 55 in an emission state to be equal to the third potential of the auxiliary electrode 308 so as to change a state of the one or more target emission portions in the emission state to an emission suppression state (gridding, par.0041); or
i) adjusting the second potential of the focusing pole 306 corresponding to one or more of the at least two target emission portions 55 in an emission state to be greater than the third potential of the auxiliary electrode 308 so as to change a state of the one or more target emission portions in the emission suppression state to an emission state (par.0041).
Allowable Subject Matter
Claims 2-10 and 21 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
With respect to claim 2, while Lemaitre and Canfield teach most aspects of the claimed invention, the prior art neither teaches nor reasonably suggests the additional limitation that the emission surface of the at least one cathode sheet forms a second acute angle with a central axis of the cathode to achieve an approximate cylindrical or spherical structure, as required by the combination as claimed. Canfield teaches that the angles of the focusing electrode planes 712 and the emitter planes may be the same or different (par.0063). However, the only disclosed embodiment shows that the angles are substantially the same (Fig.7B), and there is no teaching for a particular advantage of having the angles different such that an approximate cylindrical or spherical structure may result (essentially requiring that the focusing electrode planes 712 have steeper angles (less acute) than the emitter plane). Although it is generally known that the angle of the electrodes affects the focus of the electron beam for a given voltage bias, the prior art neither teaches nor reasonably suggests providing additional approximate curvature as claimed, absent the benefit of Applicant’s disclosure.
At best, US patent documents to Zou (US 2011/0142204 A1, Figs.3-5) teach focusing electrodes 38 having an acute angle relative to the cathode, including a curved spherical shape (Fig.4); however, there is only a singular flat emitter that has an angle of zero to the cathode axis (perpendicular to the line of emission, Fig.1). The advantage for a plurality of flat emitters, each already arranged at an acute angle relative to the central axis of the cathode as required by parent claim 1, is not evident from the prior art absent the benefit of Applicant’s disclosure. Additionally, US patent documents to Price (previously made of record) illustrate a steeper angle for the emitters and a shallower angle for the focusing electrode faces (Fig.12 of US 2017/0372863 A1).
Claims 3-10 and 21 are objected to by virtue of their dependence upon claim 2, thus incorporating the combination of allowable features.
Response to Arguments
The present amendments to the claims overcome all outstanding 35 USC 112 rejections of record.
Applicant's arguments with respect to the amendments to the claims over the prior art have been fully considered but they are not persuasive. Applicant argues that there is no insulating layer between the electrode 308 and the at least two emitter portions of Lemaitre (as is now required by claims 1, 14 and 15), nor that a third potential is applied to the electrode 308 (as required by claim 17). The Examiner respectfully disagrees on both points.
With respect to claims 1, 14 and 15, the Examiner wishes to note that the insulating layer is required to be “between” the auxiliary electrode and the emitter portions with no further details on physical or electrical requirements. As schematically illustrated in Fig.9 and described in par.0045, the electrodes are considered to be insulated from the emitter portions by one or more insulation layers, as broadly as claimed.
Second, the Examiner notes that par.0046 states that the auxiliary electrode 308 may be separately biased relative to the other focusing electrodes 300 and 400 in order to further control the focal spot position of the electron beam.
For at least these reasons, Applicant’s arguments are not persuasive.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to THOMAS R ARTMAN whose telephone number is (571)272-2485. The examiner can normally be reached Monday-Thursday 10am-6:30pm.
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THOMAS R. ARTMAN
Primary Examiner
Art Unit 2884
/THOMAS R ARTMAN/ Primary Examiner, Art Unit 2884
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