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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 1/12/2026 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Response to Amendment
The following addresses applicant’s remarks/amendments dated 7 January 2026.
Claims 1-3, 12, 14-15, 17-18, and 20 were amended. No claim was cancelled. No new claims were added. Therefore, claims 1-20 are currently pending in the current application and are addressed below.
Response to Arguments
Applicant’s arguments, see pages 7-9 of the Remarks, filed 7 January 2026, with respect to the rejection(s) of claim(s) 1 and 12 under 35 U.S.C. 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Moore et al., US 20170115381 A1 in view of Hallstig et al., US 20190086518 A1.
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 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.
Claims 1, 12, 17, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Moore et al., US 20170115381 A1 (“Moore”) in view of Hallstig et al., US 20190086518 A1 (“Hallstig”).
Regarding claim 1, Moore teaches an optical ranging system (Fig. 1, optical ranging device 30, Paragraph [0024]) comprising: a first phase-locked loop (PLL) configured to generate a first frequency signal and a second frequency signal (Fig. 5, PLL circuitry 72, Clocks [7:0] to TDC and Clocks [7:0] to laser clock control, Paragraph [0033]-[0034]; See also Paragraph [0041]-[0042]); […];an optical source (Fig. 5, laser 65, laser driver 63, laser clock control 64, Paragraph [0033]; See also Paragraph [0042]), […]; a first single-photon avalanche diode (SPAD) configured to receive a reflected optical signal (Fig 5, SPAD detector array 62, Paragraph [0033]); a time-to-digital converter (TDC) coupled to the first SPAD, wherein the TDC is configured to generate digital samples by sampling an output signal of the first SPAD under control of the second frequency signal (Fig. 5, TDC circuitry 71, Paragraph [0034]);
Moore does not teach:
a second PLL configured to generate a third frequency signal based on a control signal, wherein the control signal is formed using the first frequency signal, wherein the third frequency signal has a frequency that changes linearly over a duration of the third frequency signal;
wherein a wavelength of the optical signal emitted by the optical source is configured to be maintained at a fixed nominal value throughout an operational period of the optical ranging system that includes multiple durations of the third frequency signal;
a reference signal generator configured to generate a reference signal; and a mixer configured to generate an output signal by multiplying the reference signal and the digital samples from the TDC.
However, Hallstig teaches generating a modulating FM signal using a control signal from a PLL and VCO to introduce a linear ramp configuration between two frequencies (Fig. 11, VCO 282, PLL 283, Paragraph [0122]). The signal is passed to laser modulator which modulates the optical output signal at a light emitter to generate an envelope-frequency-modulated signal (Fig. 11, laser modulator 274, light emitter 278, Paragraph [0123]; Fig. 12C shows optical signal with maintained frequency/wavelength and modulated amplitude). Lastly, Hallstig teaches using an I/Q mixer to mix the received signal with the local oscillator signal (Fig. 11, I/Q mixer 262,264, Paragraph [0122])
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. In addition, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s digital signal processing by adding mixer to combine the reference and return signal, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Regarding claim 12, Moore discloses an optical ranging system comprising: an optical source configured to emit an optical signal (Fig. 5, laser 65, Paragraph [0033]), […]; a single-photon avalanche diode (SPAD) configured to receive a reflected optical signal (Fig. 5, SPAD detector array 62, Paragraph [0033]); a time-to-digital converter (TDC) coupled to the SPAD (Fig. 5, TDC circuitry 71, Paragraph [0034]), wherein the TDC is configured to generate first digital samples by sampling an output signal of the SPAD, wherein the first digital samples have a first sampling rate (Fig. 5, TDC circuitry 71, PLL circuitry 72, digital signal processing and control logic 73, Paragraph [0034]-[0035]); […].
Moore does not teach: an optical signal wherein an intensity of the optical signal is configured to be modulated by a chirp signal during a chirp period of the chirp signal, wherein a frequency of the optical signal is configured to remain unchanged during an operational period of the optical ranging system that includes a plurality of chirp periods and a reference signal generator configured to generate a reference signal that corresponds to the chirp signal sampled at the first sampling rate; and a mixer configured to generate an output signal by multiplying the reference signal and the first digital samples from the TDC.
However, Hallstig teaches generating a modulating FM signal using a control signal from a PLL and VCO to introduce a linear ramp configuration between two frequencies (Fig. 11, VCO 282, PLL 283, Paragraph [0122]). The signal is passed to laser modulator which modulates the optical output signal at a light emitter to generate an envelope-frequency-modulated signal (Fig. 11, laser modulator 274, light emitter 278, Paragraph [0123]; Fig. 12C shows optical signal with maintained frequency/wavelength and modulated amplitude). Lastly, Hallstig teaches using an I/Q mixer to mix the received signal with the local oscillator signal (Fig. 11, I/Q mixer 262,264, Paragraph [0122])
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. In addition, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s digital signal processing by adding mixer to combine the reference and return signal, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Claim 17 is a method claim corresponding to apparatus claim 12 and is rejected for the same reasons.
Regarding claim 20, Moore, as modified in view of Hallstig, discloses the method of claim 17, wherein the wavelength of the optical signal is maintained at a fixed nominal value during the emitting (Hallstig, Fig. 12C shows optical signal with maintained frequency/wavelength and modulated amplitude).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Claims 2, 4-9, 13, and 15-16 are rejected under 35 U.S.C. 103 as being unpatentable over Moore, as modified in view of Hallstig, in further view of Huber et al., US 20150109621 A1 (“Huber”).
Regarding claim 2, Moore, as modified in view of Hallstig, discloses the optical ranging system of claim 1.
Moore, as modified in view of Hallstig, does not teach: further comprising: a digital filter coupled to the mixer and configured to filter the output signal of the mixer; and a frequency detector coupled to the digital filter and configured to detect a peak frequency in a spectrum of an output signal of the digital filter.
However, Huber teaches a synthesizer that mixes a reference phase locked clock with a received fringe signal (Fig. 11a, synthesizer 70, reference clock 72, Paragraph [0083]). The synthesizer can contain a mixer to a phase-locked reference signal with a phase locked signal of a constant frequency. A filter is placed after the mixer to suppress unwanted signals. (Fig. 11d, mixer 84, phase-locked reference signal 72, LO signal 84, filter 86, Paragraph [0086]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore and Hallstig’s receiver circuitry by adding a mixer to mix the swept signal with a phase locked signal of constant frequency and add a filter. One of ordinary skill in the art would have been motivated to make these modifications in order to suppress unwanted mixer products, as suggested by Huber (Paragraph [0086]).
Regarding claim 4, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 2, wherein the first frequency signal has a first fixed frequency (Moore, Fig. 5, PLL circuitry 72, Clocks [7:0] to TDCs, Paragraph [0033]-[0034]; See also Paragraph [0042]), the second frequency signal has a second fixed frequency (Moore, Fig. 5, PLL circuitry 72, Clocks [7:0] to laser clock control, Paragraph [0042]), and the third frequency signal has a third frequency that changes linearly over a pre-determined period of time (Hallstig, Fig. 11, VCO 282, PLL 283, Paragraph [0122]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Regarding claim 5, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 4.
Moore, as modified in view of Hallstig and Huber, does not teach: wherein the second fixed frequency is an integer multiple of the first fixed frequency.
However, Huber teaches a circuit that contains two PLLs to create a sweep control signal for a light source and a detection clock signal. The first PLL generates a signal with a frequency of 100 MHz and the second PLL generates a signal with a frequency of 1 GHz. (Fig. 7, PLL 52, PLL 56, Paragraph [0069]-[0070]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the PLLs disclosed by Moore and Hallstig by having the second PLL’s signal frequency be an integer multiple of the first PLL’s signal frequency, which is disclosed by Huber. One of ordinary skill in the art would have been motivated to make these modifications in order to phase lock two electrical signals in order to improve flaws in image quality, as suggested by Huber (Paragraph [0072]).
Regarding claim 6, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 4, further comprising a frequency sweep circuit coupled between the first PLL and the second PLL (Hallstig, Fig. 11, VCO 282, PLL 283, Paragraph [0122]), wherein the frequency sweep circuit is configured to generate the control signal for the second PLL (Hallstig, Fig. 11, VCO 282, PLL 283, Paragraph [0122]), wherein the control signal increases linearly over the pre-determined period of time (Hallstig, Fig. 11, VCO 282, PLL 283, Paragraph [0122]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Regarding claim 7, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 6, wherein the reference signal generator is coupled between the frequency sweep circuit and the mixer (Hallstig, Fig. 11, VCO 282, PLL 283, LO signals 289, 291, I/Q mixer 262,264, Paragraph [0122]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. In addition, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s digital signal processing by adding mixer to combine the reference and return signal, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Regarding claim 8, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 4, further comprising a driver circuit for the optical source (Moore, Fig. 5, laser driver 63, Paragraph [0033]), wherein the driver circuit is coupled between the second PLL and the optical source (Hallstig, Fig. 11, VCO 282, PLL 283, laser modulator 274, light emitter 278 Paragraph [0123]), and is configured to generate a chirp signal in accordance with the third frequency signal, wherein the intensity of the optical source is modulated by the chirp signal (Hallstig, Fig. 11 and 12C, linear FM signal 217, envelope-frequency-modulated optical signal, Paragraph [0123]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Regarding claim 9, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 8, wherein the digital samples from the TDC have a first sampling rate (Moore, Fig. 5, PLL circuitry 72, clocks[7:0], TDC circuitry 71, Paragraph [0034]), wherein the reference signal corresponds to the chirp signal sampled at the first sampling rate (Hallstig, Fig. 11, VCO 282, PLL 283, LO signals 289, 291, Paragraph [0122]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Claim 13 contains the same claim limitations as claim 2 and is rejected for the same reasons.
Regarding claim 15, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 13, wherein the optical source is a laser source having a fixed nominal wavelength for a laser signal emitted by the laser source (Hallstig, Fig. 11, laser modulator 274, light emitter 278, Paragraph [0123]; Fig. 12C linear frequency envelope modulated carrier).
Moore, as modified in view of Hallstig and Huber, does not teach: and the digital filter is a low-pass filter.
However, Huber teaches a low-pass filter placed before the mixer. It would be an obvious modification to filter out both high and unwanted frequencies after the mixer. (Fig. 11d, low-pass filter 78, mixer 84, filter 86, Paragraph [0084], [0086]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the receiver circuitry, disclosed by Moore, as modified in view of Hallstig and Huber, by adding a mixer to mix the swept signal with a phase locked signal of constant frequency and add a filter. One of ordinary skill in the art would have been motivated to make these modifications in order to suppress unwanted mixer products, as suggested by Huber (Paragraph [0086]).
Regarding claim 16, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 13, wherein the mixer is a digital multiplier (Hallstig, Fig. 11, I/Q mixer 262,264, Paragraph [0122]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s clock signal to the laser clock control by adding a second PLL and VCO to generate another frequency signal that is sent to the receiver circuitry and laser driver, which is disclosed by Hallstig. In addition, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Moore’s digital signal processing by adding mixer to combine the reference and return signal, which is disclosed by Hallstig. One of ordinary skill in the art would have been motivated to make this modification in order improve detection SNR, as suggested by Hallstig (Paragraph [0185]).
Claims 3, 14, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Moore, as modified in view of Hallstig and Huber, in further view of Chong, US 20190317199 A1 (“Chong”).
Regarding claim 3, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 2, wherein the intensity of the optical signal is configured to be modulated by a chirp signal derived from the third frequency signal (Hallstig, Fig. 11, VCO 282, PLL 283, Paragraph [0122]).
Moore, as modified in view of Hallstig and Huber does not teach: wherein the optical ranging system further comprises a range calculation circuit coupled to the frequency detector and configured to calculate a distance D between the optical ranging system and a target using the detected peak frequency, wherein the range calculation circuit is configured to calculate the distance D using
D
=
C
0
×
|
Δ
f
|
2
×
(
d
f
d
t
)
, wherein C-0 is a speed of light, Δf is the detected peak frequency, and df/dt is a gradient of the chirp signal.
However, Chong teaches a LIDAR system that uses a reference and object signal to calculate the distance to an object according to the detected beat frequency and the instantaneous slope of the frequency ramp (Fig. 3, reference signal 300, object signal 302, Equation 2, Paragraph [0047]-[0048]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified digital signal processing, disclosed by Moore and Hallstig and Huber, by using Chong’s distance measurement equation to calculate the range to an object. One of ordinary skill in the art would have been motivated to make this modification in order to increase the reliability of distance calculation, as suggested by Chong (Paragraph [0048]).
Claim 14 contains the same claim limitations as claim 3 and is rejected for the same reasons.
Claim 18 is a method claim corresponding to apparatus claims 3 and 14. Claim 18 is rejected for the same reasons.
Claims 10-11 are rejected under 35 U.S.C. 103 as being unpatentable over Moore, as modified in view of Hallstig and Huber, in further view of Patanwala et al., US 20200400792 A1 (“Patanwala”).
Regarding claim 10, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 2, further comprising: a second SPAD configured to receive the reflected optical signal (Moore, Fig. 5, return SPAD array 62, Paragraph [0033]).
Moore, as modified in view of Hallstig and Huber, does not teach: and an adder circuit coupled to the first SPAD and the second SPAD, and is configured to add the output signal of the first SPAD with an output signal of the second SPAD, wherein the TDC is configured to generate the digital samples by sampling an output signal of the adder circuit under control of the second frequency signal.
However, Patanwala teaches a summation circuit where the output of each SPAD device and corresponding sampling device gets converted to a single output signal. The output signal is then provided to another sampling device with a clock signal (Fig. 6, SPAD 104, synchronous sampling devices 602, summation circuit 604, L-bit D-type flip-flop 606, Paragraph [0051]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the receiver circuitry disclosed by Moore, as modified in view of Hallstig and Huber, by adding a summation circuit after the SPAD array, which is disclosed by Patanwala. One of ordinary skill in the art would have been motivated to make this modification in order to generate a binary output value, as suggested by Patanwala (Paragraph [0008]).
Regarding claim 11, Moore, as modified in view of Hallstig and Huber, discloses the optical ranging system of claim 2, further comprising: a second SPAD configured to receive the reflected optical signal (Moore, Fig. 5, return SPAD array 62, Paragraph [0033]), […], wherein the TDC is configured to generate the digital samples by sampling an output signal of the OR gate under control of the second frequency signal (Moore, Fig. 5, TDC 37, Paragraph [0034]).
Moore, as modified in view of Hallstig and Huber, does not teach: and an OR gate, wherein a first input terminal of the OR gate is coupled to the first SPAD and a second input terminal of the OR gate is coupled to the second SPAD.
However, Patanwala teaches a combining network where the output of two spads is passed through an OR gate to produce a single output (Fig. 2, SPAD device 104, PS 202, OR gates 206).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the receiver circuitry disclosed by Moore, as modified in view of Hallstig and Huber, by placing OR gates between the SPADs and TDCs, which is disclosed by Patanwala. One of ordinary skill in the art would have been motivated to make this modification in order to generate a binary output value, as suggested by Patanwala (Paragraph [0008]).
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Moore, as modified in view of Hallstig and Huber and Chong, in further view of Sadhu et al., US 20190178993 A1 (“Sadhu”).
Regarding claim 19, Moore, as modified in view of Hallstig and Huber and Chong, discloses the method of claim 18.
Moore, as modified in view of Hallstig and Huber and Chong, does not teach: wherein performing the frequency analysis comprises: performing a Fast Fourier Transform (FFT) for the output signal of the digital filter; and finding a frequency bin of the FFT that has a highest amplitude.
However, Sadhu teaches performing a FFT on the received signal to estimate the delay in the received signal (Paragraph [0029]).
It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the TOF processing disclosed by Moore, as modified in view of Hallstig and Huber and Chong, by performing a FFT to identify the phase of the received signal. One of ordinary skill in the art would have been motivated to make this modification in order to increase the unambiguous range without trading off distance precision performance or increasing distance calculation complexity, as suggested by Sadhu (Paragraph [0021]-[0022]).
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 N NGUYEN whose telephone number is (571)270-5405. The examiner can normally be reached Monday - Friday 8 am - 5:30 pm ET.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Yuqing Xiao can be reached at (571) 270-3603. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/RACHEL NGUYEN/Examiner, Art Unit 3645
/YUQING XIAO/Supervisory Patent Examiner, Art Unit 3645
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