Prosecution Insights
Last updated: April 19, 2026
Application No. 18/476,518

SETTLED DUST MEASUREMENT SYSTEM USING PHOTORESISTORS

Non-Final OA §103
Filed
Sep 28, 2023
Examiner
STAFIRA, MICHAEL PATRICK
Art Unit
2877
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Dust Company Inc.
OA Round
3 (Non-Final)
88%
Grant Probability
Favorable
3-4
OA Rounds
2y 1m
To Grant
97%
With Interview

Examiner Intelligence

Grants 88% — above average
88%
Career Allow Rate
1110 granted / 1256 resolved
+20.4% vs TC avg
Moderate +9% lift
Without
With
+8.6%
Interview Lift
resolved cases with interview
Fast prosecutor
2y 1m
Avg Prosecution
33 currently pending
Career history
1289
Total Applications
across all art units

Statute-Specific Performance

§101
2.9%
-37.1% vs TC avg
§103
41.7%
+1.7% vs TC avg
§102
41.1%
+1.1% vs TC avg
§112
8.9%
-31.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1256 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 . 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. Claim(s) 1, 3-24 is/are rejected under 35 U.S.C. 103 as being unpatentable over WO 98/48261 in view of PARSONS et al. (2019/0072487). Claim 1, 14 WO 98/48261 discloses apparatus and method for projecting light (Fig. 1b, Ref. 1) to obtain a reference measurement using a first photoresistor (Fig. 1b, Ref. 6)(Page 5, lines 29-31); collecting dust on a platform (Fig. 1b, Ref. 2) during a collection time interval; and projecting light across the platform (Fig. 1b, Ref. 1) to obtain a dust measurement using the first photoresistor or a second photoresistor (Fig. 1b, Ref. 7)(Page 5, lines 1-28); comparing the dust measurement (Fig. 1b, Ref. 7) to the reference measurement (Fig. 1b, Ref. 6) generate a comparison result (Fig. 2, Ref. Comparator); and generating a notification when the comparison result satisfies a threshold (Fig. 2, Ref. LED Alarm; Page 6, lines 4-18). PNG media_image1.png 806 518 media_image1.png Greyscale WO 98/48261 substantially teaches the claimed invention except that it does not show using photoresistors for the measurements. PARSONS et al. (2019/0072487) shows that it is known to provide the use of photoresistors (Para. 0049) for a dust monitoring device. It would have been obvious to combine the device of WO 98/48261 with the photoresistors of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing photoresistors are easy to integrate into circuits and provide a cost-effective and simple sensor for measuring light, therefore reducing the overall cost of the detection system. WO 98/48261 substantially teaches the claimed invention except that it does not show the use of a processor and memory for executing a program. PARSONS et al. (2019/0072487) shows that it is known to provide a processor (Fig. 1B, Ref. 105) and memory (Para. 0079) for executing a program for a device that monitors dust collection. It would have been obvious to combine the device of WO 98/48261 with the processor and memory of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing the ability for interpreting and storing the data, therefore improving real-time alerts or alarms. Claim 3, 15 WO 98/48261 discloses monitoring an input voltage of the first photoresistor (Fig. 1b, Ref. 6); and generating a notification when a fluctuation in the input voltage is determined to be outside a defined input voltage range (Page 6, lines 4-17). Claim 4, 16 WO 98/48261 discloses monitoring an input voltage of the first photoresistor (Fig. 1b, Ref. 6); monitoring an input voltage of the second photoresistor (Fig. 1b, Ref. 7); generating a notification (alarm) when the input voltage of the first photoresistor (Fig. 1b, Ref. 6) is determined to be outside a defined input voltage range (Page 6, lines 4-17); and generating a notification when the input voltage of the second photoresistor (Fig. 2b, Ref. 7) is determined to be outside the defined input voltage range (Page 6, lines 4-17). Claim 5, 17 WO 98/48261 substantially teaches the claimed invention except that it does not show monitoring a conductivity of the first photoresistor in response to light; and adjusting an amount of light to which the first photoresistor is exposed when the conductivity is determined to be outside a defined conductivity range. PARSONS et al. (2019/0072487) shows that it is known to provide monitoring a conductivity of the first photoresistor (Fig. 1B, Ref. 103) in response to light; and adjusting an amount of light to which the first photoresistor (Fig. 1B, Ref. 103) is exposed when the conductivity is determined to be outside a defined conductivity range (Para. 0047, 0066-0067, 0073-0074, 0076 which shows that the light source can be controlled/adjusted and how it affects measurement) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the monitoring conductivity of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing optimal light detection in real-time, therefore improving the sensitivity of the device. Claim 6, 18 WO 98/48261 substantially teaches the claimed invention except that it does not show adjusting one or more characteristics of the light projected across the platform; or adjusting an amount of ambient light to which the first photoresistor is exposed. PARSONS et al. (2019/0072487) shows that it is known to provide adjusting one or more characteristics of the light projected across the platform; or adjusting an amount of ambient light to which the first photoresistor (Fig. 1B, Ref. 103) is exposed (Para. 0047, 0066-0067, 0073-0074, 0076 which shows that the light source can be controlled/adjusted and how it affects measurement) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the adjusting listed above with that of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing maximizing measurement accuracy and eliminate background interference, therefore optimizing sensitivity in different conditions. Claim 7, 19 WO 98/48261 substantially teaches the claimed invention except that it does not show monitoring a conductivity of the first photoresistor in response to light; monitoring a conductivity of the second photoresistor in response to the light; adjusting an amount of light to which the first photoresistor is exposed when the conductivity is determined to be outside a defined conductivity range; and adjusting an amount of light to which the second photoresistor is exposed when the conductivity is determined to be outside the defined conductivity range. PARSONS et al. (2019/0072487) shows that it is known to provide monitoring a conductivity of the first photoresistor (Fig. 1B, Ref. 103) in response to light; monitoring a conductivity of the second photoresistor (Para. 0049; one or more photo sensors) in response to the light; adjusting an amount of light to which the first photoresistor (Fig. 1B, Ref. 103) is exposed when the conductivity is determined to be outside a defined conductivity range; and adjusting an amount of light to which the second photoresistor (Para. 0049; one or more photo sensors) is exposed when the conductivity is determined to be outside the defined conductivity range (Para. 0047, 0066-0067, 0073-0074, 0076 which shows that the light source can be controlled/adjusted and how it affects measurement) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the monitoring of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing maximizing measurement accuracy and eliminate background interference, therefore optimizing sensitivity in different conditions. Claim 8, 20 WO 98/48261 substantially teaches the claimed invention except that it does not show an adjusting the amount of light to which the first and second photoresistors are exposed comprises: adjusting one or more characteristics of the light projected across the platform; or adjusting an amount of ambient light to which the first and second photoresistors are exposed. PARSONS et al. (2019/0072487) shows that it is known to provide an adjusting the amount of light to which the first (Fig. 1B, Ref. 103) and second photoresistors (Para. 0049; one or more photo sensors) are exposed comprises: adjusting one or more characteristics of the light projected across the platform (Fig. 1B, Ref. 101a); or adjusting an amount of ambient light to which the first (Fig. 1B, Ref. 103) and second photoresistors (Para. 0049; one or more photo sensors) are exposed (Para. 0047, 0066-0067, 0073-0074, 0076 which shows that the light source can be controlled/adjusted and how it affects measurement) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the adjusting of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing maximizing measurement accuracy and eliminate background interference, therefore optimizing sensitivity in different conditions. Claim 9 WO 98/48261 substantially teaches the claimed invention except that it does not show an each of the first photoresistor and the second photoresistor, measuring a conductivity of the respective photoresistor across a light range from low intensity to high intensity to generate a conductivity curve; using a machine learning model to perform curve fitting on the conductivity curves to generate a reference curve; and generating coefficients for each of the first photoresistor and the second photoresistor that map the respective conductivity curve for the respective photoresistor to the reference curve. PARSONS et al. (2019/0072487) shows that it is known to provide each of the first photoresistor (Fig. 1B, Ref. 103) and the second photoresistor (Para. 0049; one or more photo sensors), measuring a conductivity of the respective photoresistor across a light range from low intensity to high intensity to generate a conductivity curve; using a machine learning model to perform curve fitting on the conductivity curves to generate a reference curve; and generating coefficients for each of the first photoresistor (Fig. 1B, Ref. 103) and the second photoresistor (Para. 0049; one or more photo sensors) that map the respective conductivity curve for the respective photoresistor to the reference curve (Para. 0045, 0056; See Figs. 8-10) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the measuring conductivity of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing maximizing measurement accuracy and eliminate background interference, therefore optimizing sensitivity in different conditions. Claim 10 WO 98/48261 substantially teaches the claimed invention except that it does not show normalizing the conductivity measurements based on respective input voltages of the first photoresistor and the second photoresistor that are used to generate the respective conductivity curves. PARSONS et al. (2019/0072487) shows that it is known to provide normalizing (Figs. 8-10 show normalizing measurements) the conductivity measurements based on respective input voltages of the first photoresistor (Fig. 1B, Ref. 103) and the second photoresistor (Para. 0049; one or more photo sensors) that are used to generate the respective conductivity curves (Para. 0045, 0056; See Figs. 8-10) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the normalizing of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing maximizing measurement accuracy and eliminate background interference, therefore optimizing sensitivity in different conditions. Claim 11 PARSONS et al. (2019/0072487) discloses projecting light comprises projecting visible light (Page 6, line 7, “LED”). Claim 12 WO 98/48261 substantially teaches the claimed invention except that it does not show projecting light comprises projecting invisible light. PARSONS et al. (2019/0072487) shows that it is known to provide projecting light comprises projecting invisible light (Para. 0074; without ambient) for an optical device for monitoring dust collection. It would have been obvious to combine the device of WO 98/48261 with the invisible light of PARSONS et al. (2019/0072487) before the effective filing date of the claimed invention for the purpose of providing using a wavelength for maximizing measurement accuracy and eliminate background interference, therefore optimizing sensitivity in different conditions. Claim 13 WO 98/48261 and PARSONS et al. (2019/0072487) discloses the claimed invention except for the platform is retractable between a first position outside a measurement chamber and a second position inside the measurement chamber; and wherein the platform is in the second position during the collection interval. It would have been obvious to one having ordinary skill in the art at the effective filing date of the claimed invention was made to combine WO 98/48261 and PARSONS et al. (2019/0072487) with a retractable platform having a first and second position since it was well known in the art that having a retractable platform movable to different positions allows the platform to be maintained and reused for additional measurements, therefore improving measurement accuracy. The examiner takes Official Notice that the elements listed above are well-known, or to be common knowledge in the art are capable of instant and unquestionable demonstration as being well-known. Claims 21-24 WO 98/48261 and PARSONS et al. (2019/0072487) discloses the claimed invention except for the first and second photoresistor are the same photoresistor or different photoresistor. It would have been obvious to one having ordinary skill in the art at the effective filing date of the claimed invention was made to combine WO 98/48261 and PARSONS et al. (2019/0072487) with the different configurations of photoresistors since it was well known in the art that using different combinations of photoresistors improves light collection accuracy, therefore providing more accurate results. The examiner takes Official Notice that the elements listed above are well-known, or to be common knowledge in the art are capable of instant and unquestionable demonstration as being well-known. Response to Arguments Applicant’s arguments with respect to claim(s) 1, 3-24 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL PATRICK STAFIRA whose telephone number is (571)272-2430. The examiner can normally be reached M-F 6:30am-3pm. 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, Tarifur Chowdhury can be reached at 571-272-2287. 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. /MICHAEL P STAFIRA/Primary Examiner, Art Unit 2877 March 17, 2026]
Read full office action

Prosecution Timeline

Sep 28, 2023
Application Filed
Jan 17, 2025
Non-Final Rejection — §103
Jul 14, 2025
Response Filed
Sep 08, 2025
Final Rejection — §103
Mar 04, 2026
Request for Continued Examination
Mar 12, 2026
Response after Non-Final Action
Mar 17, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
88%
Grant Probability
97%
With Interview (+8.6%)
2y 1m
Median Time to Grant
High
PTA Risk
Based on 1256 resolved cases by this examiner. Grant probability derived from career allow rate.

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