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 .
The status of the 08/05/2026 claims, is as follows: Claims 1 and 3 have been amended; Claims 8-14 have been withdrawn; and Claims 1-14 are pending.
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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-6 are rejected under 35 U.S.C. 103 as being unpatentable over KR’913 (KR 20170075913, hereinafter KR’913, published on 07/04/2017) in view of Barrangan Perez (US 20070135037, hereinafter Perez)
Regarding Claim 1, KR’913 discloses an induction heating device (induction heating cooker, para. 0001), comprising:
a first working coil (induction burner 8);
a first inverter circuit (driving unit 18) configured to operate at a first driving frequency (frequency f1, indicated by kHz Table 3) that corresponds to a first required output value of the first working coil (firepower set by the input device indicated by “W” in Table 3) and supply an electric current to the first working coil (para. 0061 and 0010, Table 3);
a second working coil (induction burner 9);
a second inverter circuit (driving unit 19) configured to operate at a second driving frequency (frequency f2, indicated by kHz Table 3) that corresponds to a second required output value of the second working coil (firepower set by the input device indicated by “W” in Table 3), and supply an electric current to the second working coil (para. 0061 and 0010, Table 3); and
a controller (control unit) configured to set a difference between the first driving frequency (f1) and the second driving frequency (f2) to be equal to a predetermined noise avoidance value (values less than 2 kHz) (para. 0063 and 0004; Table 3. It is noted the audible frequency range approximately 2 kHz to 20 kHz) by adjusting a duty ratio of a switching signal input to the first inverter circuit (duty of the driving unit 18 is changed from 6/6 to 3.66/6) (para. 0038 and 0030; Table 3. “it is preferable that the control unit controls the plurality of driving units so as to coincide with the timing at which the plurality of induction burners change from a duty off state to a duty on state.”, para. 0019. The duty as shown in Table 3 is the duty of the driving units 18, 19, which is the “ON” section in one cycle of the driving units) and adjusting magnitude of the first driving frequency (frequency change to f1 from 38.9 kHz to 34 kHz; Table 3) (para. 0037-0038), when the difference between the first driving frequency and the second driving frequency is included in a first predetermined reference range (audible frequency band i.e. 2 kHz to 20 kHz) (para. 0037 and 0063),
wherein the duty ratio of the switching signal (duty i.e. 6/6 means that the induction burner operates “ON” for 6 seconds out of 6 second. The cycle is 6 seconds. Another example, 3.66/6 means that the induction burner operates “ON” for 3.66 seconds out of 6 second cycle) is defined as a ratio of an on-duty section in one cycle of the switching signal (para. 0030 and “it is preferable that the control unit controls the plurality of driving units so as to coincide with the timing at which the plurality of induction burners change from a duty off state to a duty on state.”, para. 0019. The duty as shown in Table 3 is the duty of the driving units 18, 19, which is the “ON” section in one cycle of the driving units).
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KR’913 does not disclose the second driving frequency being greater than the first driving frequency.
However, Perez discloses an induction heating device (para. 0002) comprises at least two coils that can be operated at the same time (abstract), wherein the second driving frequency (f2) being greater than the first driving frequency (f1) (para. 0023; fig. 2).
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Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the second driving frequency of KR’913 being greater than the first driving frequency as Perez, in order to incorporate known technique (i.e. f2 greater than f1) to a known device (induction cooktop) to yield a predictable result, which is to yield different heating output associated to respective heating coils.
Regarding Claim 2, KR’913 discloses the induction heating device, wherein when the difference between the first driving frequency and the second driving frequency (difference between f1 and f2 is in audible frequency band approximately 2 kHz to 20 kHz) is included in the first predetermined reference range (audible frequency band i.e. 2 kHz to 20 kHz), the controller (control unit) is configured to adjust the duty ratio of the switching signal input to the first inverter circuit to a predetermined reference duty ratio (duty from 6/6 to 3.66/6) and adjust the first driving frequency to a predetermined noise avoidance frequency (34 kHz) (frequency change to f1 i.e. from 38.9 kHz to 34 kHz; Table 3) (para. 0037-0038).
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Regarding Claim 3, KR’913 discloses the induction heating device, wherein the predetermined noise avoidance frequency (determined f1 i.e. 34 kHz) is a value obtained by subtracting the predetermined noise avoidance value (values less than 2 kHz) from the second driving frequency (f2) (para. 0038 and 0063).
Regarding Claim 4, KR’913 discloses the induction heating device, wherein the controller (control unit) is configured to increase the duty ratio of the switching signal input to the first inverter circuit (duty of driving unit 18) when an actual output value of the first working coil is less than the first required output value (set firepower) after the magnitude of the first driving frequency is changed (frequency change to f1) (para. 0009, 0032, 0037-0038, and 0021. It is noted after the frequency change to ensure the frequency difference between f1 and f2 is outside the audible range, the duty is adjusted to maintain the heating power output at the desired heating power output. The phrase “adjusted” implies that the duty is either increased or decreased such that the heating power output is at the desired power output).
Regarding Claim 5, KR’913 discloses the induction heating device, wherein the controller (control unit) is configured to decrease the duty ratio of the switching signal input to the first inverter circuit (duty associated with burner 8) when an actual output value of the first working coil is greater than the first required output value (set firepower) after the magnitude of the first driving frequency is changed (frequency change) (para. 0009, 0032, 0037-0038, and 0021. It is noted after the frequency change occurs to ensure the frequency difference is outside the audible range, the duty is adjusted to maintain the heating power output at the desired heating power output. The phrase “adjusted” implies that the duty is either increased or decreased such that the heating power output is at the desired power output).
Regarding Claim 6, KR’913 discloses the induction heating device, wherein the controller (control unit) is configured to maintain an actual output value of the first working coil (heating power output of burner 8) to be the same as the first required output value (set firepower) after the duty ratio of the switching signal input to the first inverter circuit is adjusted (duty is adjusted) (para. 0021 and 0009).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over the modification of KR’913 (KR 20170075913, hereinafter KR’913, published on 07/04/2017) and Barrangan Perez (US 20070135037, hereinafter Perez) as applied to claim 1 above, further in view of Christiansen (US 20160381736)
Regarding Claim 7, the modification discloses substantially all of the claimed features as set forth above. KR’913 discloses when the frequency difference is greater than the lowest frequency of the audible frequency range (i.e. 2 kHz), the controller determines that noise is generated (para. 0063).
The modification does not disclose the controller is configured to set the first driving frequency and the second driving frequency to have a same value when the difference between the first driving frequency and the second driving frequency is included in a second predetermined reference range.
However, Perez further discloses the controller is configured to determine that noise is generated when the difference between the first driving frequency and the second driving frequency (fs) is included in a second predetermined reference range (between 2 kHz and 14 kHz) (para. 0023-0024) (it is noted when the frequency difference fs is in the range between 2 kHz and 14 kHz, the noise is audible to human’s ears).
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Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to configure the controller of KR’913 to detect the noise is generated when the frequency difference is in the range between 2 kHz and 14 kHz as further taught by Perez, in order to allow the burners to operate simultaneously at the frequency difference that is outside of the audible range i.e. between 2 kHz and 14 kHz. The range between 2 kHz and 14 kHz constitute the second predetermined reference range.
The modification does not disclose the controller is configured to set the first driving frequency and the second driving frequency to have a same value when the difference is included in the second predetermined reference range.
However, Christiansen discloses the controller (control unit) is configured to set the first driving frequency and the second driving frequency to have a same value (same working frequency) (para. 0044) in order to cancel acoustic interference noise.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to configure the controller of KR’913 in view of Perez to set the first driving frequency and the second driving frequency to have a same value when the difference is included in the second predetermined reference range (i.e. between 2 kHz and 14 kHz of Perez) as taught by Christiansen, in order to remedy the noise by executing the frequency change by the setting the frequency of the first driving signal and the frequency of the second driving signal to be the same when the difference is in the audible range namely i.e. the second predetermined reference range between 2 kHz and 14 kHz of Perez. Doing so would cancel the noise when the burners are operated simultaneously.
Response to Amendment
With respect to the specification objection: since a new abstract has been provided, therefore the specification objection is withdrawn.
With respect to the claim objection: since amendment was made to claim 3, therefore the claim objection is withdrawn.
Response to Arguments
Applicant's arguments filed on 08/05/2026 have been fully considered but they are respectfully not persuasive because:
Applicant’s Arguments: with respect to claim 1 on p. 8-9 of the Remarks, “The "Duty" of KR'913 Does Not Correspond to the Claimed Duty Ratio
Claim 1 requires adjustment of the ratio of an on-duty section within one cycle of a
switching signal input to the first inverter circuit.
In contrast, Table 1 and paragraph [0030] of KR'913 expressly define the "duty" as
an operating time of an induction burner within a duty cycle measured in seconds. For
example, a duty of 1.1/6 means that the induction burner operates for 1.1 seconds during a
six-second period and remains stopped for the remaining 4.9 seconds. See paragraph [0030] of KR'913.
Accordingly, the duty of KR'913 is a burner-level duty that controls operation and
stoppage of the induction burner itself. The duty ratio of claim 1, on the other hand, is the
ratio of the on-duty section within one cycle of the inverter switching signal.
The two concepts therefore are two different control levels:
• KR'913: a duty for turning the induction burner as a whole ON and OFF during a multi-second control period; and
• Claim 1: a duty ratio representing the on-duty section within one cycle of an inverter s
witching signal.
The mere fact that KR'913 uses the term "duty" does not establish that its burner level duty corresponds to the inverter switching-signal duty ratio recited in claim 1.
Examiner’s Responses:
The applicant’s arguments are respectfully not persuasive because the duty ratio as shown in Table 3 of KR’913 constitutes the duty ratio of the switching signal to the first inverter circuit/driving unit because para. 0026 of KR’913 “a first and second driving unit (18), (19) that operates the first and second induction burners (8), (9) respectively by a control signal of a control unit (20)” and para. 0019 of KR’913 states “the control unit controls the plurality of driving units so as to coincide with the timing at which the plurality of induction burners change from a duty off state to a duty on state.”. As stated in para. 0030, the duty is expressed as “ON” time/duty cycle. For example, duty 1.1/6 means the driving units/induction burners operates “ON” for 1.1 second out of 6-second cycle. KR’913 discloses after the frequency change, the duty is adjusted to maintain the heating power output at the desired heating power output (para. 0009, 0037-0038). Duty is understood to refer to the duty of the driving unit 18, 19.
Moreover, it is conventionally known as disclosed in Bunya (US 20210227644) that the controller controls the heating power of the burner by changing the on duty (on/off ratio) of the switching element of the inverter circuit 23 of the induction coil (para. 0098, 0092-0093). The controller of Bunya set the driving frequency of one coil to be higher than the driving frequency of an adjacent coil such that the frequency difference is outside the audible range.
Applicant’s Arguments: with respect to claim 1 on p. 9-10 of the Remarks, The Firepower and Duty Control of KR'913 Is Technically Different
from the Claimed Control
“KR'913 uses the relationship between firepower and resonance frequency. More
specifically, KR'913 changes a selected firepower to indirectly change a resonance frequency
and adjusts the burner operating-time duty to maintain accumulated power before and after
the firepower change.
The control flow of KR'913 may therefore be summarized as follows:
change in selected firepower -----+ indirect change in resonance frequency -----+ adjustment of
burner operating-time duty -----+ maintenance of accumulated power
In contrast, the claimed invention adjusts the magnitude of the first driving frequency so
that the difference between the first and second driving frequencies is set to the
predetermined noise avoidance value. The duty ratio of the switching signal input to the first
inverter circuit is adjusted to compensate for a change in the output of the first working coil
that may result from the frequency adjustment.
The control flow of the claimed invention may therefore be summarized as follows:
adjustment of the first driving frequency-----+ setting the difference between the first and
second driving frequencies to the predetermined noise avoidance value -----+ compensation
for the resulting output change by adjusting the inverter switching-signal duty ratio
Thus, KR'913 indirectly changes a resonance frequency by changing a selected
firepower. In contrast, the claimed invention adjusts the first driving frequency itself to
establish the predetermined frequency difference.
Further, the duty of KR'913 is a burner-level control variable used to regulate the overall
operating time of the burner and maintain accumulated power. In contrast, the claimed duty ratio of the claimed invention is an inverter switching-signal-level control variable used to
compensate for an output change associated with the driving-frequency adjustment.
Accordingly, KR'913 fails to disclose or suggest the features of claim 1.
Examiner’s Responses:
The applicant’s arguments are respectfully not persuasive because the claim merely requires the controller….by adjusting a duty ratio of the switching signal input to the first inverter circuit and adjusting magnitude of the first driving frequency. As shown in Table 3, para. 0037-0038, the controller executes the frequency change control to f1 (from 38.9 kHz to 34 kHz) to ensure the difference is outside of the audible range and then adjusts the duty ratio of the driving unit (from 6/6 to 3.66/6). By this adjustment, the difference between the frequency of the first inverter burner 8 and the second inverter burner 9 is outside of the audible range.
As set forth in the previous argument, the duty of KR’913 in Table 3 is the operating “ON” timing of the driving unit 18 because the “ON” timing of the driving unit 18 coincides with the “ON” timing of the inverter burner 8.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Bunya (US 20210227644) discloses the controller controls the heating power of the burner by changing the on duty (on/off ratio) of the switching element of the inverter circuit 23 of the induction coil (para. 0098).
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 extension fee 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 date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BONITA KHLOK whose telephone number is (571)270-7313. The examiner can normally be reached on M-F: 9:00am-6pm.
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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/BONITA KHLOK/ Examiner, Art Unit 3761
/IBRAHIME A ABRAHAM/ Supervisory Patent Examiner, Art Unit 3761
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