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 .
Drawings
In the prosecution of corresponding application EP 23163794, the Examining Division found:
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Applicant replied:
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Figs 3 and 5 were corrected to have the on voltage of the switch, Vce (V) be only positive or zero.
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The drawings are objected to because Figs 3 and 5 do not correctly represent the behavior of the invention, as described above. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Objections
Claims 5 and 6 are objected to because of the following informalities:
In claim 5 at line 3, “predetermined” should be corrected to –a predetermined--.
In claim 5 at line 5, “predetermined” should be corrected to –a predetermined--.
In claim 6 at line 2, “predetermined” should be corrected to –a predetermined--.
In claim 6 at line 4, “predetermined” should be corrected to –a predetermined--.
Appropriate correction is required.
Claim Interpretation
No claim limitations are interpreted under 112(f).
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 2 and 3 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 2 recites “the zero-crossing point of the on voltage of the first switch, which is a time point when the on voltage of the first switch changes from a positive voltage to a negative voltage.” However, according to the prosecution of EP 23163794, the voltage on the switch is only positive or zero, and it is never negative. Thus, the switch does not have a negative voltage, and the zero-crossing point as claimed is indefinite. The same is true for the corresponding limitation for the second switch.
Claim 3 recites “a switching frequency of the second control signal.” Although a switching element has a switching frequency, the specification does not describe how to interpret a “switching frequency” of a control signal. It is not clear whether this is the frequency or some other feature of the control signal. For the purpose of examination, the limitation has been interpreted as and may be corrected to -- a switching frequency of the second switching element--. This is in accordance with the instant specification at ¶79.
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.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-4 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Gelber (US 2017/0303345).
Regarding claim 1, Gelber discloses:
An induction heating apparatus (¶1), comprising:
a rectifying circuit (206, ¶30) that rectifies an alternating current (AC) voltage;
a smoothing circuit (unlabeled capacitor in Fig 3) that connects to the rectifying circuit and that smooths a voltage that is output from the rectifying circuit;
a first switch (208, ¶31) having a first terminal that connects to a working coil, and a second terminal that connects to the smoothing circuit;
a second switch (209) that connects to the first switch in parallel;
a driving circuit (¶31 “gate drivers”) that supplies a first switching signal to the first switch, and a second switching signal to the second switch; and
a controller (¶31 “controller”) configured to output a first control signal corresponding to the first switching signal, and a second control signal corresponding to the second switching signal, wherein a rising edge timing of the first switching signal is synchronized with a zero-crossing point of an on voltage of the first switch (¶21 “the independent gate drivers may initiate gate pulses in accordance with such control techniques (e.g. at a zero crossing event”)), and a rising edge timing of the second switching signal is synchronized with a zero-crossing point of an on voltage of the second switch (¶21, ¶37).
Regarding claim 2, Gelber discloses:
the rising edge timing of the first switching signal is synchronized with the zero-crossing point of the on voltage of the first switch, which is a time point when the on voltage of the first switch changes from a positive voltage to a negative voltage (¶21, ¶37), and the rising edge timing of the second switching signal is synchronized with the zero-crossing point of the on voltage of the second switch, which is a time point when the on voltage of the second switch changes from a positive voltage to a negative voltage (¶35 describes a turning on a first switch to initiate a charging phase, followed by a resonant/oscillation phase, and then closing a second switch to recharge. Taken together with the zero voltage switching of ¶37, this implies that between each resonance phase and the subsequent recharging phase, the voltage goes from positive to zero.).
Regarding claim 3, Gelber discloses:
a resonance frequency of the working coil is twice a switching frequency of the first switching element or a switching frequency of the second control signal (¶35 discloses that the resonance frequency is twice the frequency of either switch, since they alternate. Because the control signals correspond to the frequency of the switch actions, this meets the limitation. ¶44).
Regarding claim 4, Gelber discloses:
a switching frequency of the first switch is same as a switching frequency of the second switch (¶34 “the first and second charging phase subsets can be distributed in an alternating manner” Alternating implies the same frequency.).
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 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Gelber (US 2017/0303345) in view of Payne (US 4,473,732).
Regarding claim 5, Gelber discloses:
the controller is configured to turn on and turn off the first switch and the second switch alternately (¶34 “the first and second charging phase subsets can be distributed in an alternating manner”),
Gelber does not explicitly disclose:
the first switch is turned on after predetermined first time passes from a time point at which the second switch is turned off, and
the second switch is turned on after predetermined second time passes from a time point at which the first switch is turned off.
Gelber ¶35 describes a resonant phase to allow the energy stored by induction heating coil 202 during each charging phase to oscillate between switch 208 turning off and switch 209 turning on, and vice versa.
Payne teaches controlling switches for an induction cooker circuit either by a circuit including a voltage comparator (see Fig 4), or by a logic circuit with a timer (col 9 line 59 – col 10 line 14). Using the circuit with the timer provides that “the desired relationship between current pulse duration or ON time and the amplitude of the supply, are provided by programming each transition of the control signal to occur at the appropriate count.”
COMBINATION
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the control of Gelber to include and use a timer to coordinate control of the switches, as taught by Payne, to obtain he benefit of providing the desired relationship between current pulse duration or ON time and the amplitude of the supply.
Regarding claim 6, Gelber as modified by Payne teaches:
the rising edge timing of the first switching signal is a time point at which predetermined third time passes from the rising edge timing of the second switching signal, and
the rising edge timing of the second switching signal is a time point at which predetermined fourth time passes from the rising edge timing of the first switching signal (Gelber discloses each portion of this cycle and Payne teaches controlling the cycle with a timer, such that any two points in the cycle would be separated by a predetermined time period.).
Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Kondo (US 2018/0375442) teaches an induction heating resonant type inverter (¶3) having sets of 3 switches in parallel, which provides a reduced frequency of 1/3, or 1/N, on each switch (¶24).
Kagan (US 2006/0076338) teaches “a plurality of smaller IGBTs in parallel can be used to drive the load, instead of a single larger IGBT. This may decrease the cost of the switching component of the power supply circuit, particularly as the desired power level increases. Utilizing a plurality of smaller IGBTs enables one to increase the frequency of the signal (number of pulses per unit time) and thus increase the power, while not exceeding the current limit of the switch” (¶49).
Kim (US 2023/0422356) teaches:
An induction burner has a problem that low power usage of the burner occurs at a lower frequency that is not able to properly perform zero voltage switching. Kim teaches a controller that provides a switching control signal vg that is turned on after a delay time tg has passed since the falling edge of the switching timing reference signal S50. That is, the switching control signal, which is a PWM signal, may be determined to be turned on after the delay time tg has passed since the falling edge of the switching timing reference signal and to be turned off after a pulse width ton which is determined by the resonance tanks 15, 16 (¶81). Kim teaches that the rising edge voltage coincides with the on voltage going from positive to zero.
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Kleveland (US 20030179595 A1) is cited in Kondo. Kleveland takes in DC voltage and puts out sinusoidal voltage (¶30) for a resonant load, which is an induction heater.
Touzelbaev (US 2015/0194883) teaches “a timing circuit, which senses approach of zero-crossing point (when AC input voltage crosses zero voltage) by monitoring switching frequency of a peak current mode controller and provides control signal of a presettable time duration for storage capacitor discharge.”
KR 102201065 B1 discloses “indicating a turn-on period of the switching circuit based on comparing a result of performing a counting operation with a first reference value.”
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TOPAZ L ELLIOTT whose telephone number is (571)270-5851. The examiner can normally be reached Monday-Friday 9 a.m. - 4 p.m. EST.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Ibrahime Abraham can be reached on (571) 270-5569. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/TOPAZ L. ELLIOTT/Primary Examiner, Art Unit 3761
/IBRAHIME A ABRAHAM/Supervisory Patent Examiner, Art Unit 3761