Prosecution Insights
Last updated: April 19, 2026
Application No. 18/359,585

INDIRECT TIME OF FLIGHT (TOF) DEPTH SENSING FOR EYE TRACKING

Non-Final OA §102§103
Filed
Jul 26, 2023
Examiner
WOLDEMARYAM, ASSRES H
Art Unit
3642
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Meta Platforms Technologies, LLC
OA Round
1 (Non-Final)
83%
Grant Probability
Favorable
1-2
OA Rounds
2y 10m
To Grant
95%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allow Rate
577 granted / 696 resolved
+30.9% vs TC avg
Moderate +12% lift
Without
With
+11.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
41 currently pending
Career history
737
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
41.2%
+1.2% vs TC avg
§102
26.5%
-13.5% vs TC avg
§112
28.4%
-11.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 696 resolved cases

Office Action

§102 §103
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 . DETAILED ACTION This office action is in regards to application # 18/359,585 that was filed on 07/26/2023. Claims1-20 are currently pending and are under examination. 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. Claim(s) 1-2, 7-9, and 14-16 is/are rejected under 35 U.S.C. 102(a)(1)/(a)/(2) as being anticipated by Trail (US2018/0205943). Regarding Claim 1, Trail discloses an eye tracking system (Fig. 1-2), comprising: a light source (265, Fig. 2-3) to transmit a light beam onto an eye(410, Fig. 4), wherein the transmitted light beam is modulated (para. [0023], ‘…the illumination source 265 may be modulated in time, frequency, or both….’); a detector (270, Fig. 2-3) to detect a reflected light beam from a surface of the eye (420, Fig. 4); a phase detection block to determine a phase difference between the transmitted light beam and the detected light beam (430, Fig. 4); and a controller (310, Fig. 3) communicatively coupled to the light source, the detector, and the phase detection block(Fig. 3), the controller to: coordinate a timing of transmission and detection between the light source and the detector (para. [0047], ‘…The controller coordinates how the illumination source emits light and how the imaging device captures light…’); and determine a distance to the surface of the eye based on the phase difference (440. Fig. 4). Regarding Claim 2, Trail discloses an eye tracking system (Fig. 1-2) wherein the light source is a laser source (para. [0020], ‘…laser-type light emitters…’, [para. [0023], ‘laser diodes’ as a light source). Regarding Claim 7, Trail discloses an eye tracking system (Fig. 1-2) further comprising: an imaging lens to focus the reflected light beam onto the detector (270, Fig. 2-3, para. [0025, “…The imaging device 270 may include, although not limited to, a charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) digital image sensor and an optical element. The optical element may be one or more lenses, a high-pass, low-pass, or band-pass filter…”). Regarding Claim 8, Trail discloses an eye tracking system (Fig. 1-2) wherein the transmitted light beam is modulated using a signal with a frequency in a range from about 2 GHz to about 5 GHz (para. [0023], ‘…the emitted temporally varying irradiance pattern is a sinusoidal or square wave in nature comprising one or more frequencies, e.g., one or more frequencies between approximately 30 MHz and 10 GHz…’, i.e. range between about 2 GHz and 5 GHz is included in 30 MHz and 10 GHz). Regarding Claim 9, Trail discloses a near-eye display device(Fig. 1), comprising: a display to provide an image on an eye (525, Fig. 5); and an eye tracking system(Fig. 1-2), comprising: a laser source(265, Fig. 2-3) to transmit a modulated laser beam (para. [0023], ‘…the illumination source 265 may be modulated in time, frequency, or both….’) onto the eye(410, Fig. 4); a detector (270, Fig. 2-3) to detect a reflected laser beam from a surface of the eye; a phase detection block to determine a phase difference between the transmitted laser beam and the detected laser beam(430, Fig. 4); and a controller(310, Fig. 3) communicatively coupled to the laser source, the detector, and the phase detection block(Fig. 3), the controller to: coordinate a timing of transmission and detection between the laser source and the detector (para. [0047], ‘…The controller coordinates how the illumination source emits light and how the imaging device captures light…’); and determine a distance to the surface of the eye based on the phase difference(440. Fig. 4). Regarding Claim 14, Trail discloses a near-eye display device(Fig. 1) further comprising: an imaging lens to focus the reflected light beam onto the detector (270, Fig. 2-3, para. [0025, “…The imaging device 270 may include, although not limited to, a charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) digital image sensor and an optical element. The optical element may be one or more lenses, a high-pass, low-pass, or band-pass filter…”). Regarding Claim 15, Trail discloses method for eye tracking in a near-eye display device (Fig. 1-2), the method comprising: modulating a laser beam para. [0023], ‘…the illumination source 265 may be modulated in time, frequency, or both….’, via laser diode, para. [0020]); transmitting the modulated laser beam onto an eye ( via 265, Fig. 2-3, 410, Fig. 4)); detecting a reflected laser beam from a surface of the eye(via 270, Fig. 2-3, 420, Fig. 4); determining a phase difference between the transmitted laser beam and the detected laser beam(430, Fig. 4); and determining a distance to the surface of the eye based on the phase difference(440. Fig. 4). Regarding Claim 16, Trail discloses method for eye tracking in a near-eye display device (Fig. 1-2) further comprising: sensing a three-dimensional (3D) feature of the eye based on the determined distance (para. [0030], “…Based on multiple calculated distances from the detector of the imaging device 320 to different surfaces of the eye 230, the controller 310 can determine three-dimensional coordinates of surfaces in at least a portion of the eye 230 and update a three-dimensional model of at least the portion of the eye 230. Finally, the controller 310 can estimate a position and orientation of the eye 230 and track the eye 230 based on the updated model of the eye 230…”). 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) 3-4, 10-11, and 17-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Trail (US2018/0205943) in view of Na et al. (US2017/0075421). Regarding Claim 3, Trail is silent, but Na teaches an eye tracking system wherein the transmitted light beam is modulated using a pulsed signal (Fig. 1D-1I, para. [0065]), and the phase detection block is a quadrature analog front end detection block (para. [0065], “…first readout circuit reads the collected charge, Q90, in a quadrature phase with respect to the emitted light pulses, such as the 90 degree phase. In this instance, the second readout circuit can read the collected charge, Q270, in the other quadrature phase with respect to the emitted light pulses,…”). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase detection block of the eye tracking system disclosed in Trail with the quadrature analog front end detection as taught in Na with a reasonable expectation of success because it provides full 360 degree phase detection range, improved signal to noise ratio, as well as reduced Sensitivity to Amplitude Fluctuations. Regarding Claim 4, Trail is silent, but Na teaches an eye tracking system wherein the phase detection block is to detect a phase difference using: φ = arctan (Q3- Q4) / (Q1- Q2), where Q1, Q2, Q3, and Q4 represent respective charges for quadrature detection channels C1, C2, C3, and C4 over an integration time (para. [0065], Figs, 1D, 1E, 1F, 1G, for eye tracking system with 4 read out circuits C1-C4, the phase difference would be given as indicated in the above equation from Fig. 1F (phases for charge collection). Fig. 1I shows shifted phases for charge collection). Regarding Claim 10, Trail is silent, but Na teaches an eye tracking system wherein the phase detection block is to determine the phase difference between the transmitted laser beam and the detected laser beam through quadrature analog front end detection(Fig. 1D-1I, para. [0065]), and the phase detection block is a quadrature analog front end detection block (para. [0065], “…first readout circuit reads the collected charge, Q90, in a quadrature phase with respect to the emitted light pulses, such as the 90 degree phase. In this instance, the second readout circuit can read the collected charge, Q270, in the other quadrature phase with respect to the emitted light pulses,…”). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase detection block of the eye tracking device of the near eye display device disclosed in Trail with the quadrature analog front end detection as taught in Na with a reasonable expectation of success because it provides full 360 degree phase detection range, improved signal to noise ratio, as well as reduced Sensitivity to Amplitude Fluctuations. Regarding Claim 11, Trail is silent, but Na teaches an eye tracking system wherein the phase detection block is to detect a phase difference using: φ = arctan (Q3- Q4) / (Q1- Q2), where Q1, Q2, Q3, and Q4 represent respective charges for quadrature detection channels C1, C2, C3, and C4 over an integration time (para. [0065], Figs, 1D, 1E, 1F, 1G, for eye tracking system with 4 read out circuits C1-C4, the phase difference would be given as indicated in the above equation from Fig. 1F (phases for charge collection). Fig. 1I shows shifted phases for charge collection). Regarding Claim 17, Trail is silent, but Na teaches a method an eye tracking comprising modulating the laser beam comprises: modulating the laser beam with a pulsed signal(Fig. 1D-1I, para. [0065]); and determining the phase difference between the transmitted laser beam and the detected laser beam comprises: employing a quadrature analog front end detection technique(para. [0065], “…first readout circuit reads the collected charge, Q90, in a quadrature phase with respect to the emitted light pulses, such as the 90 degree phase. In this instance, the second readout circuit can read the collected charge, Q270, in the other quadrature phase with respect to the emitted light pulses,…”).. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase detection method of the eye tracking disclosed in Trail with the quadrature analog front end detection technique as taught in Na with a reasonable expectation of success because it provides full 360 degree phase detection range, improved signal to noise ratio, as well as reduced Sensitivity to Amplitude Fluctuations. Regarding Claim 18, Trail is silent, but Na teaches a method an eye tracking wherein determining the phase difference between the transmitted laser beam and the detected laser beam comprises: detecting the phase difference using: φ = arctan (Q3- Q4) / (Q1- Q2), where Q1, Q2, Q3, and Q4 represent respective charges for quadrature detection channels C1, C2, C3, and C4 over an integration time (para. [0065], Figs, 1D, 1E, 1F, 1G, for eye tracking system with 4 read out circuits C1-C4, the phase difference would be given as indicated in the above equation from Fig. 1F (phases for charge collection). Fig. 1I shows shifted phases for charge collection). Claim(s) 5-6, 12-13, and 19-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Trail (US2018/0205943) in view of Hammack (US 3996590). Regarding Claim 5, Trail discloses an eye tracking system (Fig. 1-2) wherein the transmitted light beam is modulated using a sinusoidal signal (para. [0023], ‘…the emitted temporally varying irradiance pattern is a sinusoidal or square wave in nature comprising one or more frequencies, e.g., one or more frequencies between approximately 30 MHz and 10 GHz…’). Trail is silent, but Hammack teaches an object tracking system wherein the phase detection block is an analog homodyne phase detection block (homodyne circuit, detection data before A/D 2059/2060 are analog, Fig. 67; col. 91, lines 37-68). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase detection block of the eye tracking system disclosed in Trail with the analog homodyne phase detection as taught in Hammack with a reasonable expectation of success because it provides high sensitivity and noise rejection as well as it offers superior signal-to-noise ratio (SNR) by directly converting signals to DC, eliminating intermediate frequency (IF) stages. Regarding Claim 6, Trail is silent, but Hammack teaches an object tracking system wherein the phase detection block comprises: two 90-degree phase-shifted (via 2054/2055, Fig. 67) mixers (2052/2053, Fig. 67) to extract phase and amplitude; and a low pass filter (2056/2057, Fig. 67) for each mixer to block a sum frequency (col. 91, lines 37-68). Regarding Claim 12, Trail discloses an eye tracking system (Fig. 1-2) wherein the phase detection block is to determine the phase difference between the transmitted laser beam and the detected laser beam (430, Fig. 4). Trail is silent, but Hammack teaches an object tracking system wherein the phase detection is performed via analog homodyne phase detection (homodyne circuit, detection data before A/D 2059/2060 are analog, Fig. 67; col. 91, lines 37-68). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase detection block of the eye tracking system disclosed in Trail with the analog homodyne phase detection as taught in Hammack with a reasonable expectation of success because it provides high sensitivity and noise rejection as well as it offers superior signal-to-noise ratio (SNR) by directly converting signals to DC, eliminating intermediate frequency (IF) stages. Regarding Claim 13, Trail is silent, but Hammack teaches an object tracking system wherein the phase detection block comprises: two 90-degree phase-shifted (via 2054/2055, Fig. 67) mixers (2052/2053, Fig. 67) to extract phase and amplitude; and a low pass filter (2056/2057, Fig. 67)for each mixer to block a sum frequency (col. 91, lines 37-68). Regarding Claim 19, Trail discloses a method of an eye tracking (Fig. 1-2)wherein modulating the laser beam comprises: modulating the laser beam with a sinusoidal signal para. [0023], ‘…the emitted temporally varying irradiance pattern is a sinusoidal or square wave in nature comprising one or more frequencies, e.g., one or more frequencies between approximately 30 MHz and 10 GHz…’). Trail is silent, but Hammack teaches an object tracking method wherein determining the phase difference between the transmitted laser beam and the detected laser beam comprises: employing an analog homodyne phase detection technique (homodyne circuit, detection data before A/D 2059/2060 are analog, Fig. 67; col. 91, lines 37-68). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase detection method of the eye tracking disclosed in Trail with the analog homodyne phase detection method as taught in Hammack with a reasonable expectation of success because it provides high sensitivity and noise rejection as well as it offers superior signal-to-noise ratio (SNR) by directly converting signals to DC, eliminating intermediate frequency (IF) stages. Regarding Claim 20, Trail discloses a method of an eye tracking (Fig. 1-2) wherein determining the phase difference between the transmitted laser beam and the detected laser beam comprises: extracting phase and amplitude using two 90-degree phase-shifted(via 2054/2055, Fig. 67) mixers(2052/2053, Fig. 67); and blocking a sum frequency using a low pass filter (2056/2057, Fig. 67) for each mixer(col. 91, lines 37-68). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Trail (US 2018/0196509) discloses a head-mounted display (HMD) includes an eye tracking system that determines user's eye tracking information based on combining structured light information and time-of-flight information. The eye tracking system includes an illumination source, an imaging device and a controller. The illumination source modulates a structured light by a carrier signal and illuminates a user's eye with the modulated structured light. The imaging device includes a detector that captures the modulated structured light. The detector comprises a plurality of pixel groups, each pixel group receiving a control signal determining when a pixel group captures light, the control signal causing pixel groups to capture light at different times relative to other pixel groups. The controller determines phases of the carrier signal based on intensities of light received by different pixel groups and generates depth information related to surfaces of the user's eye, which is used to model and track the user's eye. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ASSRES H WOLDEMARYAM whose telephone number is (571)272-6607. The examiner can normally be reached Monday-Friday 8AM-5PM. 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, Joshua Huson can be reached at 571-270-5301. 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. Assres H. Woldemaryam Primary Examiner (Aeronautics and Astronautics) Art Unit 3642 /ASSRES H WOLDEMARYAM/Primary Examiner, Art Unit 3642
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Prosecution Timeline

Jul 26, 2023
Application Filed
Mar 20, 2026
Non-Final Rejection — §102, §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

1-2
Expected OA Rounds
83%
Grant Probability
95%
With Interview (+11.7%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 696 resolved cases by this examiner. Grant probability derived from career allow rate.

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