Prosecution Insights
Last updated: April 19, 2026
Application No. 18/447,594

LIGHT EMITTER DRIVER CIRCUIT FOR SMOKE DETECTOR

Non-Final OA §103
Filed
Aug 10, 2023
Examiner
PREVIL, DANIEL
Art Unit
2685
Tech Center
2600 — Communications
Assignee
Carrier Corporation
OA Round
1 (Non-Final)
86%
Grant Probability
Favorable
1-2
OA Rounds
2y 4m
To Grant
98%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
1326 granted / 1547 resolved
+23.7% vs TC avg
Moderate +13% lift
Without
With
+12.6%
Interview Lift
resolved cases with interview
Typical timeline
2y 4m
Avg Prosecution
38 currently pending
Career history
1585
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
55.6%
+15.6% vs TC avg
§102
11.0%
-29.0% vs TC avg
§112
14.6%
-25.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1547 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. Claims 1-19 are rejected under 35 U.S.C. 103 as being unpatentable over Buck (US 4,688,021) in view of Mochizuki et al. (US 5,670,948). Regarding claims 1, 10, 17, Buck discloses a driver circuit for a light emitter of a smoke detector (abstract), the driver circuit comprising: a transistor comprising a base terminal, a collector terminal, and an emitter terminal (fig. 2; col. 2, lines 29-48), wherein the collector terminal of the transistor is adapted to be operatively connected to the light emitter of the smoke detector (fig. 2; fig. 2; col. 2, lines 29-59); a resistor of a predefined resistance configured to be connected to the emitter terminal of the transistor (col. 4, lines 41-68); and a controller operatively configured at the base terminal (fig. 2), wherein the controller is configured to: determine, at a manufacturing stage of the driver circuit, a first base voltage to be supplied to the base terminal of the transistor to enable the transistor to supply a predefined current to the light emitter (fig. 2); determine, at the manufacturing stage, a first resistor voltage across the resistor when the first base voltage is supplied to the base terminal (fig. 2; col. 4, lines 41-68); set, before each smoke detection process, a value of the base voltage supplied to the base terminal to the first base voltage (col. 4, lines 8-40); determine a second resistor voltage across the resistor (col. 4, lines 8-40); compare the first resistor voltage with the second resistor voltage; determine a difference between the first resistor voltage and the second resistor voltage based on the comparison (col. 4, lines 8-68). Buck discloses all the limitations set forth above but fails to explicitly disclose adjust the value of the base voltage supplied to the base terminal based on the determined difference to enable the transistor to supply the predefined current to the light emitter. However, Mochizuki discloses adjust the value of the base voltage supplied to the base terminal based on the determined difference to enable the transistor to supply the predefined current to the light emitter (col. 8, lines 62-67; col. 9, lines 1-10). Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was first filed to incorporate the feature of Mochizuki within the system of Buck in order to accurately operate the devices by precluding signals exceeding the threshold thereby increasing the reliability of the system. Regarding claims 2, 11, Buck discloses wherein the predefined current corresponds to a constant current to be supplied to the light emitter at a predefined temperature (col. 4, lines 20-40). Regarding claim 3, Buck discloses wherein the predefined temperature is room temperature (col. 4, lines 20-40). Regarding claim 4, Buck discloses wherein the transistor is a Darlington pair transistor or single Transistor (col. 4, lines 20-40). Regarding claim 5, Buck and Mochizuki disclose all the limitations set forth in claim 1 and Mochizuki further discloses wherein, based on one or more of the second resistor voltage across the resistor, the adjusted base voltage to be supplied to the base terminal to supply the predefined current to the light emitter, and the predefined resistance of the resistor, the controller is configured to determine a temperature at an area of interest (AOI) where the driver circuit or the smoke detector is installed (col. 8, lines 62-67; col. 9, lines 1-10). Regarding claim 6, Buck discloses wherein the controller of the driver circuit is a computing unit of the smoke detector, wherein the smoke detector comprises the light emitter and a light receiver (col. 2, lines 6-28). Regarding claim 7, Buck discloses wherein the controller of the driver circuit is different from a computing unit of the smoke detector, wherein the controller of the driver circuit is in communication with a computing unit of the smoke detector (fig. 2). Regarding claims 8, 12, Buck discloses wherein the controller comprises: an analog to digital converter (ADC) to monitor voltage across the resistor; and a digital to analog converter (DAC) to supply an analog voltage to the base terminal of the transistor (fig. 1-fig. 2). Regarding claim 9, Buck discloses wherein the controller comprises: a processor; and a memory coupled to the processor and configured to store the values of the first voltage and the second voltage (fig. 1-fig. 2). Regarding claim 13, Buck discloses wherein the light emitter and the light receiver are enclosed within a hollow enclosure having a smoke chamber that is adapted to receive smoke therewithin (fig. 1-fig. 2). Regarding claim 14, Buck discloses wherein the controller is configured to: enable the transistor to supply the predefined current to the light emitter to enable the light emitter to emit photons within the smoke chamber; detect smoke within the smoke chamber based on a count of photons received by the light receiver upon getting reflected from particles of the smoke within the smoke chamber (fig. 1-fig. 2). Regarding claim 15, Buck discloses wherein the controller is configured to generate alarm signals when the count of reflected photons within the smoke chamber exceeds a predefined value (fig. 1-fig. 2). Regarding claim 16, Buck discloses wherein the device is adapted to be installed in one or more areas of interest (AOI) comprising one or more of an HVAC duct, room, hall, staircase, vehicle interior, and storage space (fig. 1-fig. 2). Regarding claim 18, Buck discloses wherein the method comprises the step of determining a temperature at an area of interest (AOI) where the driver circuit or the smoke detector is installed, based on one or more of the second resistor voltage across the resistor, the adjusted base voltage to be supplied to the base terminal to supply the predefined current to the light emitter, and the predefined resistance of the resistor (col. 2, lines 6-59). Regarding claim 19, Buck discloses wherein when the difference between the first resistor voltage and the second resistor voltage is zero, the method comprises the step of supplying the first base voltage to the base terminal of the transistor (fig. 1-fig. 2; col. 2, lines 6-59). Allowable Subject Matter Claims 20-21 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The following is a statement of reasons for the indication of allowable subject matter: In combination with all the limitations in the claims, the prior arts fail to teach or make obvious: wherein when the difference between the first resistor voltage and the second resistor voltage is positive, the method comprises the steps of: computing, by the controller, a first compensation value that corresponds to the difference between the first resistor voltage and the second resistor voltage, divided by a first correction factor ranging from 0.1 to 16; adjusting, by the controller, the base voltage to be supplied to the base terminal to a value equal to a sum of the first base voltage and the first compensation value; and supplying, by the controller, the adjusted base voltage to the base terminal. wherein when the difference between the first resistor voltage and the second resistor voltage is negative, the method comprises the steps of: computing, by the controller, a second compensation value that corresponds to the difference between the second resistor voltage and the first resistor voltage, divided by a second correction factor ranging from 0.1 to 16; adjusting the base voltage to be supplied to the base terminal to a value equal to a difference between the first base voltage and the second compensation value; and supplying, by the controller, the adjusted base voltage to the base terminal. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Simard (US 2010/0026379) discloses power…….control device. Kim et al. (US 2014/0111343) discloses composite……sensor therein. Naik et al. (US 2024/0022060) discloses fault protection…….controllers. Solomon (US 4,300,133) discloses smoke detector. Seki et al. (US 2004/0124227) discloses welding condition monitoring device. Honda (US 2012/0228506) discloses solid state imaging device. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL PREVIL whose telephone number is (571)272-2971. The examiner can normally be reached Monday-Friday from 9:30 AM -6:00 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, Wang Quan-Zhen can be reached at 571 272 3114. 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. DP January 7, 2026 /DANIEL PREVIL/ Primary Examiner, Art Unit 2685
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Prosecution Timeline

Aug 10, 2023
Application Filed
Jan 07, 2026
Non-Final Rejection — §103
Apr 08, 2026
Response Filed

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

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Prosecution Projections

1-2
Expected OA Rounds
86%
Grant Probability
98%
With Interview (+12.6%)
2y 4m
Median Time to Grant
Low
PTA Risk
Based on 1547 resolved cases by this examiner. Grant probability derived from career allow rate.

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