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
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 03/24/2025 was being considered by the examiner.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1, 5, 6 and 8 is/are rejected under 35 U.S.C. 102(a)(1) as anticipated by Mimura et al. (JP 2004-319298 A).
With regard to claim 1, Mimura teaches “An imaging X-ray source assembly with multiple filaments” and “a plurality of filaments configured to emit electrons when a respective current passes through each filament of the plurality of filaments” (X-ray tube 17 contains LF and SF, with heating of the selected filament followed by application of high voltage to generate the respective focal X-ray output), [0013], [0015], [0019] - [0020], (Figure 1, see elements 17, LF, SF & A).
Mimura teaches “a filament transformer configured to transfer electrical energy to the plurality of filaments” and “a filament driver configured to supply electrical energy to the plurality of filaments via the filament transformer” (transformer 8 supplies the selected filament; inverter 2 supplies its primary. The driver assembly includes the low-side signaling inverter 4 and winding 5 under the construction stated above), [0015] - [0020], (Figures 1 & 2, see elements 2, 4, 5 & 8).
Mimura teaches “a plurality of switches, each switch being connected to a respective one of the filaments and configured to regulate the respective current through the respective filament” (triac 28A controls LF and triac 28B controls SF; the selected path passes heating current and the other path is disabled), [0033] - [0034], (Figure 4, see elements 28A, 28B, LF & SF).
Mimura teaches “a controller connected to the plurality of switches and the filament driver” (the high-side receiving circuit comprising winding 12, rectifier 14 and capacitor 15, together with transistor 29 and the gate-control network, receives the driver signal and controls the two triacs), [0017], [0023], [0033] - [0034], (Figures 2 & 4).
Mimura teaches “the connection between the filament driver and the controller is galvanically isolated” (the low-side transmitting winding 5 and high-side receiving winding 12 face across insulation 18 and distance M, rather than a conductive connection between those windings), [0018], [0025], (Figures 1 & 2, see elements 5, 12, 18 & M).
Mimura further teaches “the filament driver is configured to provide a filament driver output signal to the controller” (inverter 4 drives winding 5; its energized or unenergized output conveys the selection state to receiving winding 12), [0017], [0019] - [0020], (Figures 1 & 2).
Mimura teaches “the controller is configured to control the plurality of switches by respective switch control signals based on the filament driver output signal” (the received and rectified signal supplies the gate path of 28B and turns transistor 29 on to suppress the 28A gate drive; the alternative received state allows the 28A gate drive), [0033] - [0034], (Figure 4, see elements 12, 14, 15, 28A, 28B & 29).
With regards to claim 5, Mimura teaches “the switches are semiconductor switches” (triacs 28A and 28B), [0033] - [0035], (Figure 4).
With regards to claim 6, Mimura teaches “an anode configured to generate X-rays when impinged with electrons at a focal spot,” with first and second filaments emitting electrons to respective focal spots and “the second focal spot is different from the first focal spot in size, location and/or shape” (anode A receives electrons from LF or SF, generating a large or small focus; the size alternative is met), [0015], [0019] - [0020], (Figure 1, see elements A, LF & SF).
With regards to claim 8, Mimura teaches “power to switch at least one of the switches is derived from windings of the filament transformer” (transformer 8’s secondary charges capacitor 31 through diode 32, producing the gate supply for triac 28A through resistor 30A), [0034], (Figure 4, see elements 8, 28A, 30A, 31 & 32).
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.
Claims 2 and 3 are rejected under 35 U.S.C. §103 as being unpatentable over Mimura et al. (JP 2004-319298 A) in view of Arai et al. (EP 1 463 023 A2).
With regards to claim 2, Mimura teaches the claimed invention according to claim 1 and through its alternative, see Figure 3, a semiconductor arrangement.
Mimura teaches transformer-derived local gate power (capacitor 31 charged through diode 32 from transformer 8 in its Figure 4 alternative), [0034], (Figure 4). This supplies a disclosed starting point for powering added local control circuitry; adequate supply capacity for that circuitry is part of the proposed adaptation, not an express Figure 3 feature.
Mimura, however, does not expressly teach:
(1) “the switch control signals are pulsed control signals”; and
(2) “the controller is configured to control each of the switches to switch with a duty cycle larger than 0% and less than 100%.”
The original rectified selection signal establishes maintained branch states, [0017], [0031] - [0032].
Arai teaches deficiency (1), “the switch control signals are pulsed control signals” (pulse-control unit 212 generates the signal at FPCON that turns filament-power switch 50 on and off), [0023], [0046], [0099] - [0104], (Figures 1, 3 & 8).
Arai teaches the nonzero, noncontinuous duty operation in deficiency (2) (switch 50 generates the filament pulse voltage, whose ordinary duty ratio is 5–20%).
Applying that disclosed control to each existing selectable branch is the modification explained below, [0023], [0053], [0080]. The pulse generator defines duty by pulse width divided by pulse cycle; polarity control accommodates the switch type, [0024], [0100] - [0104], (Figure 8).
In view of the utility of controlling filament heating power through switch conduction time, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to apply Arai’s pulse-control technique to each transistor/FET branch of Mimura. Both references concern electrical heating of an electron-emitting filament in vacuum, making the heating-control teaching reasonably pertinent despite their different X-ray and display outputs.
With regards to claim 3, Mimura teaches the claimed invention according to claim 2 but fails to expressly teach “the controller is configured to control at least one of the plurality of switches to switch with a duty cycle larger than 10% and less than 90%.”
Arai teaches an ordinary filament-pulse duty range of 5–20%, including a 20% endpoint within the claimed interval. The duty is that of power applied through switch 50, not the duty of a display grid or the high logic level of an active-low gate signal, [0023] - [0024], [0053], [0080].
In view of the utility of limiting average filament heating power through the conduction fraction, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to operate at least one selected branch of the claim 2 combination at Arai’s disclosed 20% endpoint. The heating supply would be selected for the intended filament power at that conduction fraction. This applies an expressly disclosed operating point to the same switched-heating function and predictably produces a duty inside the claimed interval.
Claim 4 is rejected under 35 U.S.C. §103 as being unpatentable over Mimura et al. (JP 2004-319298 A) in view of Arai et al. (EP 1 463 023 A2), as applied to claim 2 above, and further in view of Durakiewicz, (“Electron emission controller with pulsed heating of filament,” International Journal of Mass Spectrometry and Ion Processes, Vol. 156 (1996), Pages 31–40).
With regards to claim 4, Mimura teaches the inherited arrangement as mapped for claim 2 above, with Arai supplying the pulse-control technique and the stated rationale for applying it. Claim 4 depends on claim 2, not claim 3. Mimura, however, does not expressly teach “the pulsed control signal has a pulse length smaller than a characteristic thermal response time of the respective filament.” The Arai passages applied above do not establish this thermal comparison.
Durakiewicz teaches pulsed heating of an electron-emitting filament by a transistor-controlled supply, (Pages 32 - 35), (Figures 1 - 4). The reported rhenium filament operates at 100–350 Hz, (Page 34, Figure 3 and accompanying text). The thermal heat-dissipation analysis and temperature observations give a characteristic time of approximately 0.1–0.2 seconds, (Pages 39 - 40, Section 6, Equations 11 - 17). The heating waveform has on-pulses shorter than its repeating period, (Page 35, Figure 4).
The numerical comparison is calculated from those disclosures: a 100–350 Hz repetition frequency gives a complete period of approximately 2.9–10 milliseconds, which is below 100–200 milliseconds. Each on-pulse is shorter still. This establishes the pulse/thermal relationship in the reported example; it does not assign that specimen’s thermal constant to Mimura’s filaments, Durakiewicz, (Pages 34 - 35 & 39 - 40).
In view of the utility of sustaining thermionic heating with intermittent electrical input, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to select the pulse timing of the claim 2 combination according to Durakiewicz’s demonstrated relationship: each selected filament’s on-pulse would be shorter than its applicable thermal response.
Arai supplies controllable pulse width and cycle; Durakiewicz supplies the thermal relationship for pulsed thermionic heating. Selecting timing relative to the filament’s response would predictably provide short heating pulses while retaining thermal energy between pulses.
Claim 7 is rejected under 35 U.S.C. §103 as being unpatentable over Mimura et al. (JP 2004-319298 A), as applied to claim 1 above, in view of Furbee et al. (US 4,685,118 A).
With regards to claim 7, Mimura teaches the inherited arrangement for the reasons in the rejection of claim 1 above. It also expressly permits an optical signal between low- and high-voltage portions using light-emitting and light-receiving elements, [0028]. Mimura, however, does not expressly teach “the controller is connected to the filament driver via an optical fiber or wireless connection” through the optical-fiber alternative applied here (a fiber carrying the selection signal).
Furbee teaches the optical-fiber connection (fiber 152 carries the output of low-side LED 150 to high-side phototransistor 146). The receiver controls coil 144 and contacts 142/143, which gate the respective filament switches 132/134. Rectifier 148 derives receiver/relay power from the AC filament supply at 122C/122L; the fiber provides electrical insulation between the low-side transmitter and high-side receiver, (Col. 7, Lines 31 - 62), (Figure 5).
In view of the utility of transmitting a filament-selection command across the high-voltage boundary without a conductive control lead, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to implement Mimura’s disclosed optical alternative using Furbee’s fiber-linked transmitter, receiver and associated filament-selector control. The low-side driver would retain inverter 2 for heating power and use the optical transmitter for its selection output. Transformer 8 would feed the two filament branches and the rectified receiver supply, while the fiber receiver and contact-controlled gates would select the respective semiconductor current paths. This adopts the disclosed pair-selector function, with matching local power and control circuitry, and predictably preserves galvanic isolation.
Claims 9 and 15 are rejected under 35 U.S.C. §103 as being unpatentable over Mimura et al. (JP 2004-319298 A) in view of Khutoryansky et al. (US 5,901,197 A).
With regards to claim 9, Mimura teaches the claimed invention according to claim 1 but fails to expressly teach “the X-ray source assembly is programmable to control the respective filament currents” (programmability is required of the assembly, not necessarily of the isolated high-side controller).
Khutoryansky teaches “programmable to control the respective filament currents” through microprocessor 52’s programmable selection of the filament energization path, Khutoryansky, (Col. 5, Lines 64 - 67), (Col. 6, Lines 1 - 27), (Figure 5, see element 52).
In view of the utility of repeatable programmed selection of the filament to receive heating current, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to add Khutoryansky’s programmable selection control to Mimura’s low-side command interface, thereby making the assembly programmable while preserving its isolated signal transmission and respective filament-current switching.
With regards to claim 15, Mimura teaches “providing steps” by the identified filaments, respective switches and isolated controller; the “transferring” and “supplying steps” are performed when inverter 2 drives transformer 8 and the selected filament branch. The driver-output and resulting gate-control relationships are the same as mapped for claim 1, [0015] - [0020], [0033] - [0034], (Figures 1 & 4).
Mimura further teaches binary selection input and selection before X-ray generation in CT operation, [0019] - [0020], [0029].
Mimura, however, does not expressly teach “A computer-implemented method of controlling a plurality of respective filament currents with an X-ray source assembly” insofar as a computer executes that selection.
Khutoryansky teaches computer-implemented filament selection by programmed microprocessor 52, (Col. 5, Lines 64 - 67), (Col. 6, Lines 1 - 27), (Col. 7, Lines 8 - 13), (Figures 5 & 6). Its nearly identical filaments serve its wear-balancing scheme, (Col. 4, Lines 29 - 42); it also delays changes until an exposure ends, (Col. 6, Lines 40 - 52).
In view of the utility of automatic, repeatable filament selection, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to implement Mimura’s low-side command with Khutoryansky’s programmed microprocessor control. The computer would issue the selected command before exposure, and the existing isolated receiver would control the respective current paths. This transfers the selection-control technique while preserving focal-size selection, without imposing equal-wear alternation between unequal filaments.
Conclusion
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/DJURA MALEVIC/Examiner, Art Unit 2884
/UZMA ALAM/Supervisory Patent Examiner, Art Unit 2884
