Prosecution Insights
Last updated: October 04, 2026
Application No. 18/282,735

FILTER DEVICE FOR CLEANING AIR, EMBODIED AS A FACE MASK

Final Rejection §103
Filed
Sep 18, 2023
Priority
Mar 19, 2021 — DE 102021106813.4 +2 more
Examiner
SIPPEL, RACHEL T
Art Unit
3785
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Universität Kassel
OA Round
2 (Final)
52%
Grant Probability
Moderate
3-4
OA Rounds
9m
Est. Remaining
99%
With Interview

Examiner Intelligence

Grants 52% of resolved cases
52%
Career Allowance Rate
425 granted / 811 resolved
-17.6% vs TC avg
Strong +58% interview lift
Without
With
+58.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 10m
Avg Prosecution
39 currently pending
Career history
846
Total Applications
across all art units

Statute-Specific Performance

§101
4.2%
-35.8% vs TC avg
§103
49.3%
+9.3% vs TC avg
§102
15.3%
-24.7% vs TC avg
§112
26.3%
-13.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 811 resolved cases

Office Action

§103
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 . Amendment This office action is responsive to the amendment filed on 6/24/26. As directed by the amendment: claims 16, 18-20 and 24-30 have been amended, claims 1-15 and 23 have been canceled, and no new claims have been added. Thus, claims 16-32 are presently pending in the application. 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 (i.e., changing from AIA to pre-AIA ) 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 16-18, 20, 24-25, 27 and 29-30 are rejected under 35 U.S.C. 103 as being unpatentable over Charlot (DE 102010006883 see English translation provided by examiner) in view of Al Ahmad et al. (11,071,337). Regarding claim 16, in fig. 1 Charlot discloses a filter device 10 for rendering viruses harmless (Page 3, lines 29-31), comprising: at least one planar air permeable carrier member (10 and 12) configured as a face mask (Page 4, lines 10-12); electrical conductors (14 and 16, Page 3, line 7) applied to the at least one planar air permeable carrier member between which an electrical potential is applied (Page 3, lines 8-11), a voltage source (18, Charlot), wherein the electrical conductors (14 and 16) are connected on a planar air permeable carrier member (10 and 12) of the at least one planar air permeable carrier member to separate poles of the voltage source (Fig. 1), wherein the electrical conductors are arranged relative to one another (Fig. 1), and wherein the voltage source is designed to apply an electrical voltage such that an electric field with a field strength can be generated between the electrical conductors (abstract), the electrical conductors being spaced apart, but is silent that the electrical conductors are spaced apart by a distance of 1 µm to 100 µm and a field strength in the range from 104 V/m to 106 V/m. However, Al Ahmad teaches electrical conductors that are spaced apart by a distance of 0.004 µm to 0.5 µm (4 nm to 500 nm Col. 5, ll. 66-67) and a field strength of 20 M V/m (206 V/m). Al Ahmad discloses the claimed invention except for a distance of 1 µm to 100 µm and a field strength in the range from 104 V/m to 106 V/m. It would have been obvious to one having ordinary skill in the art at the time the invention was made to modify the distance to 1 µm to 100 µm and the field strength to a range from 104 V/m to 106 V/m., since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art and it appears that a distance of 1 µm to 100 µm and a field strength in the range from 104 V/m to 106 V/m would perform equally as well at protecting a user from viruses. In re Aller, 105 USPQ 233. Regarding claim 17, the modified Charlot discloses that the electrical conductors are electrical wires (Page 3, line 7 Charlot). Regarding claim 18, the modified Charlot is silent regarding that the electrical conductors are spaced apart by a distance of 5 µm to 20 µm or of 8 µm to 12 µm. The modified Charlot discloses the claimed invention except for a distance of 5 µm to 20 µm or of 8 µm to 12 µm. It would have been obvious to one having ordinary skill in the art at the time the invention was made to modify the distance to 5 µm to 20 µm or of 8 µm to 12 µm, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art and it appears that a distance of 5 µm to 20 µm or of 8 µm to 12 µm would perform equally as well at protecting a user from viruses. In re Aller, 105 USPQ 233. Regarding claim 20, the modified Charlot discloses that the electrical conductors between which the electrical potential is applied are applied to the at least one planar air permeable carrier member in parallel with one another and/or extending in a linear manner with respect to one another (Fig. 1 shows some portions of 14 and 16 extending in a linear manner with respect to one another, Charlot). Regarding claim 24, the modified Charlot discloses that the voltage source has a voltage of 0.1 V to 10 V or of 0.5 V to 5 V (Page 3, lines 8-9 Charlot) or of 1 V; and/or the voltage source is a battery (Page 3, line 14, Charlot), a rechargeable battery, or an electrical capacitor (Page 3, line 14, Charlot); and/or the voltage source is arranged at (near) the face mask (near the face mask, fig. 1 Charlot) or is integrated in the face mask. Regarding claim 25, the modified Charlot discloses that at least one air permeable protective member (22 and 20, see fig. 3 Charlot) that extends in a planar manner and is applied in front of and/or behind the at least one planar air permeable carrier member (22 and 20, see fig. 3 Charlot). Regarding claim 27, the modified Charlot discloses that the at least one air permeable protective member includes a first protective member (20 Charlot) and a second protective member (22 Charlot), and wherein the electrical conductors are arranged between the first protective member and the second protective member (see fig. 3, Charlot). Regarding claim 29, the modified Charlot discloses a protective member (20 and 22, Fig. 3 Charlot) arranged at both sides of the at least one planar air permeable carrier member (20 and 22, Fig. 3 Charlot), but is silent regarding that a flexible sandwich structure is formed. However, Al Ahmad teaches a flexible sandwich structure (Col. 5, ll. 6-8, abstract). It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the modified Charlot’s sandwich with a flexible sandwich, as taught by Al Ahmad, for the purpose of providing adaptability to the user’s face during use. Regarding claim 30, in fig. 1 Charlot discloses a method of operating a filter device 10 for rendering viruses harmless (Page 3, lines 29-31), comprising: providing a filter device 10 having at least one planar air permeable carrier member (10 and 12) configured as a face mask (Page 4, lines 10-12); arranging electrical conductors (14 and 16, Page 3, line 7) relative to one another on the at least one planar air permeable carrier member (Fig. 1) between which an electrical potential is applied (Page 3, lines 8-11); the electrical conductors being connected on a planar air permeable carrier member of the at least one planar air permeable carrier member to separate poles of a voltage source (18, Fig. 1); flowing through the at least one planar air permeable carrier member and thus through intermediate spaces between the electrical conductors a flow of air (Page 3, lines 8-11); acting by the electrical potential on viruses that are moved between the electrical conductors by the flow of air (Page 3, lines 29-31); and applying an electrical voltage with the voltage source such that an electric field has a field strength generated between the electrical conductors, but is silent regarding that the field strength is in the range from 104 V/m to 106 V/m. However, Al Ahmad teaches a field strength of 20 M V/m (206 V/m). Al Ahmad discloses the claimed invention except a field strength in the range from 104 V/m to 106 V/m. It would have been obvious to one having ordinary skill in the art at the time the invention was made to modify the field strength to a range from 104 V/m to 106 V/m., since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art and it appears that a field strength in the range from 104 V/m to 106 V/m would perform equally as well at protecting a user from viruses. In re Aller, 105 USPQ 233. Claims 19 and 21-22 are rejected under 35 U.S.C. 103 as being unpatentable over Charlot and Al Ahmad, as applied to claim 16 above, in further view of Jeon (KR 20150115589 see English translation provided by examiner). Regarding claim 19, the modified Charlot is silent regarding that the electrical conductors have cross-sectional dimensions of 1 µm to 100 µm or of 5 µm to 20 µm or of 10 µm. However, Jeon teaches electrical conductors having cross-sectional dimensions of 1 µm to 100 µm (10 to 500 microns, page 7, second to last paragraph, 20 to 100 microns, page 7, last paragraph) or of 5 µm to 20 µm or of 10 µm. It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the modified Charlot’s cross-sectional dimensions with cross-sectional dimensions of 1 µm to 100 µm, as taught by Jeon, for the purpose of providing an alternate wire size having the predictable results of providing an electrical conductor for denaturing viruses. Regarding claim 21, the modified Charlot is silent regarding that the electrical conductors each have a coating and are woven to one another. However, Jeon teaches that the electrical conductors each have a coating (page 7, second to last paragraph and last paragraph) and are woven to one another (Page 4, 5th full paragraph). It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the modified Charlot’s electrical conductors with electrical conductors with coatings that are woven together, as taught by Jeon, for the purpose of providing an alternate electrical conductor structure and configuration having the predictable results of providing a structure for denaturing viruses. Regarding claim 22, the modified Charlot is silent regarding that the electrical conductors are woven with polymer threads to form a conductor lattice on the carrier member. However, Jeon teaches that the electrical conductors are woven with polymer threads (polyurethan yarn, Page 8, paragraph 2) to form a conductor lattice on the carrier member. It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the modified Charlot’s electrical conductors with the addition of polymer threads, as taught by Jeon, for the purpose of providing an alternate electrical conductor structure having the predictable results of providing a structure for denaturing viruses. Claim 26 is rejected under 35 U.S.C. 103 as being unpatentable over Charlot and Al Ahmad, as applied to claim 25 above, in further view of Yidi (10,808,338). Regarding claim 26, the modified Charlot discloses that the at least one planar air permeable carrier member and/or the at least one protective member is/are a filter layer (20, Charlot), but is silent regarding that the at least one planar air permeable carrier member and/or the at least one protective member is/are formed from a textile or from a fiber mat. However, Yidi teaches at least one planar air permeable carrier member and/or the at least one protective member is/are formed from a textile or from a fiber mat (Col. 4, ll. 15-24). It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the modified Charlot’s at least one protective member behind the planar carrier member with a textile or fiber mat, as taught by Yidi, for the purpose of providing an alternate filtering structure having the predictable results of filtering out particulates for a user. Claim 28 is rejected under 35 U.S.C. 103 as being unpatentable over Charlot and Al Ahmad, as applied to claim 23 above, in further view of Fabian et al. (2018/0078798). Regarding claim 28, the modified Charlot is silent regarding a solar cell that is electrically connected to the voltage source, the solar cell being arranged at the face mask or being integrated in the face mask. However, Fabian teaches a solar cell [0140] that is electrically connected to the voltage source [0140], the solar cell being arranged at the face mask or being integrated in the face mask ([0140] the solar cell is located with the battery in a housing of the face mask [0119]). It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the modified Charlot’s voltage source with the addition of a solar cell, as taught by Fabian, for the purpose of providing charging to the voltage source. Claims 31-32 are rejected under 35 U.S.C. 103 as being unpatentable over Charlot and Al Ahmad, as applied to claim 30 above, in view of Petrovic et al. (2021/0369903). Regarding claim 31, the modified Charlot does not explicitly recite that an interaction of electrical voltage or of the electrical potential or of an electrical field is performed on an outer structure of the viruses by the action of the electrical potential between the electrical conductors on the viruses. However, Petrovic teaches that an interaction of electrical voltage or of the electrical potential or of an electrical field is performed on an outer structure of the viruses by the action of the electrical potential between the electrical conductors on the viruses [0023]. 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 modified Charlot’s method with the addition of interaction of electrical voltage or of the electrical potential or of an electrical field is performed on an outer structure of the viruses by the action of the electrical potential between the electrical conductors on the viruses, as taught by Petrovic, for the purpose of destroying or denaturing viruses. Regarding claim 32, the modified Charlot discloses that the viruses have spike proteins ([0023] Petrovic), the spike proteins being manipulated by the action of the electrical potential between the electrical conductors on the viruses such that a subsequent attachment of the viruses to human or animal cells is prevented ([0023] Petrovic, due to the denaturization of the viruses). Response to Arguments Applicant's arguments filed 6/24/26 have been fully considered but they are not persuasive. Applicant argues on page 9 that Charlot does not contemplate the use of an electric field to interact directly with viruses passing between the conductors and to render them harmless. This argument is not taken well since Charlot discloses the use of an electric field to interact directly with viruses passing between the conductors and to render them harmless on Page 3, lines 29-31, where Charlot recites that the electric field attracts viruses and traps them in the electric field, such that pathogens are removed from the stream of air. This teaching of Charlot renders the viruses harmless since they do not reach the user when they are trapped. Applicant argues on pages 9-10 that Al Ahmad’s field strength of 206 V/m is not close to the claimed range from 104 V/m to 106 V/m. Examiner disagrees since 106 V/m and 206 V/m are the same order of magnitude. Further, it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art and it appears that a field strength in the range from 104 V/m to 106 V/m would perform equally as well at protecting a user from viruses. In re Aller, 105 USPQ 233. Conclusion 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 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 RACHEL T SIPPEL whose telephone number is (571)270-1481. The examiner can normally be reached M-F 9:00-5:00 PM. 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, Timothy Stanis can be reached at (571) 272-5139. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /RACHEL T SIPPEL/Primary Examiner, Art Unit 3785
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Prosecution Timeline

Sep 18, 2023
Application Filed
Mar 24, 2026
Non-Final Rejection mailed — §103
Jun 16, 2026
Interview Requested
Jun 22, 2026
Examiner Interview Summary
Jun 22, 2026
Applicant Interview (Telephonic)
Jun 24, 2026
Response Filed
Sep 14, 2026
Final Rejection mailed — §103 (current)

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Prosecution Projections

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Expected OA Rounds
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Grant Probability
99%
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