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 .
This is the first office action on the merits and is responsive to the papers filed 02/08/2024. Claims 1-13 are currently pending and examined below.
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d).
Information Disclosure Statement
The information disclosure statement submitted by Applicant is in compliance with the provision of 37 CFR 1.97, 1.98 and MPEP § 609. They have been placed in the application file and the information referred to therein has been considered as to the merits.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION. —The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 8 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as failing to set forth the subject matter which the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the applicant regards as the invention.
It is unclear from the language of claim 8 the following:
The measurement device according to claim 7, wherein a spectral linewidth of the laser light is smaller than one tenth of the modulation frequency. Claim 7 does not specify any range for the modulation frequency, it is not clear how to determine a spectral linewidth of the laser light to be smaller than one tenth of the modulation frequency.
For purposes of examination, the modulation frequency will be between 500 MHz and 10 GHz, inclusive as indicated in claim 1.
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, 2, 4 are rejected under 35 U.S.C. 103 as being unpatentable over Marra et al. (US 20190120961 A1, “Marra”) in view of Francois Bondu (US 20130100973 A1, “Bondu”).
Regarding claim 1, Marra teaches a measurement method ([0001]) comprising:
emitting a transmission signal comprising at least one light pulse, wherein an amplitude of an intensity of the light pulse is modulated with a modulation frequency and the modulation frequency is between 500 MHz and 10 GHz, inclusive (Fig. 4, TX, claim 1; [0065]-[0067]; [0066], 1.8 GHz and see also, claim 2),
detecting a receiving signal comprising at least a part of the transmission signal that is reflected from an external object (Fig. 4, RX, claim 1; [0069]),
selecting at least one frequency component of the receiving signal corresponding to the modulation frequency of the transmission signal (Marra teaches feeding the received signal to frequency adjustment unit 60, mixing the received signal down from the modulation frequency using receiver-side mixer 76, and suppressing unwanted components using low-pass filter 78 ([0061], [0068-0069]),
determining a distance to the external object from a time difference between the emission of the transmission signal and the detection of the selected frequency component of the receiving signal (Marra teaches that the time interval between the transmitted modulated pulse and received modulated pulses is the light time-of-flight, and that pulse evaluation and phase evaluation determine/refine distance ([0067], [0070-0072]; Fig. 4),
Marra fails to explicitly teach but Bondu teaches wherein one light pulse of the transmission signal is generated by a superposition of two unmodulated sub-pulses with light of different frequency (Bondu teaches a dual-frequency laser producing two beams of different light frequencies and orthogonal polarizations, and teaches a polarizer on the path of the two superposed beams. See Bondu [0012-0018], [0030-0035]; Sole Figure.), and
wherein the modulation frequency corresponds to a frequency difference of the light of the two sub-pulses (Bondu teaches that the output beam is sinusoidally amplitude-modulated by the beat frequency Fs = F1 − F2. See Bondu [0041-0042], [0056].).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Marra’s distance-measuring optoelectronic sensor to generate Marra’s high-frequency periodically modulated light pulse using Bondu’s optical frequency-beating technique. Marra teaches that high modulation frequencies, including at least 500 MHz, 1 GHz, and 2 GHz or more, improve distance-measurement accuracy, while Bondu teaches producing high-frequency amplitude-modulated optical radiation by superposing two laser beams of different optical frequencies so that the modulation is produced at the beat/difference frequency. The modification would have predictably provided Marra’s desired high-frequency amplitude modulation using a known optical beat source.
Regarding claim 2, Marra in view of Bondu, teaches the measurement method according to claim 1, wherein the amplitude of the intensity of the light pulse is modulated with a sinusoidal signal (Marra teaches converting the basic clock into a sinusoidal signal by a low-pass filter and then mixing up to the modulation frequency (Marra, [0019], [0063]- [0064]; Fig. 3, sine/clock generation 62 and low-pass 64)).
Regarding claim 4, Marra in view of Bondu, teaches the measurement method according to claim 1, wherein a duration of the light pulse is at least ten times the inverse modulation frequency (Marra teaches a pulse/burst of 10 ns modulated at 1.8 GHz. A 1.8 GHz period is about 0.56 ns, so 10 ns includes about 18 periods, satisfying “at least ten times the inverse modulation frequency.” [0066]; Fig. 4.).
Claims 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Marra et in view of Bondu and De Mersseman (WO 2017205170 A1, “De Mersseman”).
Regarding claim 5, Marra in view of Bondu, fails to explicitly teach the measurement method according to claim 1, wherein the selection of a frequency component comprises a Fourier transform of the receiving signal.
However, De Mersseman teaches spectral resolution using a DFT and teaches that FFT is a computationally efficient technique for calculating the DFT and implements a filter bank over the frequency domain ([0063-0064]; Fig. 9). De Mersseman also teaches that FFT spectral analysis implements a filter bank of discrete range bins ([0074]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Marra’s received-signal evaluation to use the FFT/DFT spectral selection taught by De Mersseman because Marra already analyzes received modulation information using receiver-side mixing and filtering, and De Mersseman teaches FFT processing as an efficient known way to select frequency-domain components and improve LiDAR signal-to-noise ratio.
Regarding claim 6, Marra in view of Bondu, fails to explicitly teach the measurement method according to claim 1, wherein a velocity of the external object is determined using a Doppler shift of the modulation frequency in the receiving signal.
De Mersseman teaches that moving objects result in variable-amplitude range-bin pulses, which enable Doppler frequency measurement via spectral resolution ([0060-0061]). De Mersseman further teaches two-dimensional FFT processing for Doppler frequency detection and extraction of object relative velocity related to Doppler frequency [0076], [0081-0083].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further configure Marra’s modulated LiDAR receiver to determine velocity from Doppler shift as taught by De Mersseman, because Marra already uses high-frequency optical modulation and received phase/time-of-flight information for distance measurement, and De Mersseman teaches that Doppler processing of modulated LiDAR signals provides target velocity information
Claims 7, 9, 12 are rejected under 35 U.S.C. 103 as being unpatentable over Marra et in view of Zhang et al. (US 5091913 A, “Zhang”).
Regarding claim 7, Marra teaches a measurement device, comprising:
a transmission unit configured to emit a transmission signal during operation, the transmission signal comprising at least one light pulse in which an amplitude of an intensity is modulated with a modulation frequency (Marra teaches light transmitter 12 transmitting a periodically modulated pulse/burst as the transmission signal (Figs. 1, 4, [0045]; claims 1-2).),
a receiving unit configured to detect a receiving signal during operation, the receiving signal comprising at least a part of the transmission signal reflected from an external object (Marra teaches light receiver 18 receiving light remitted/reflected from object 16 (Figs. 1, 4, [0045]; claims 1-2)), and
an evaluation unit configured to analyze the receiving signal during operation, and that is configured to select at least one frequency component of the receiving signal at the modulation frequency and to determine at least a distance to the external object from a time-of-flight of the transmission signal determined therefrom (Marra teaches control/evaluation unit 24 evaluating the reception signal, determining light time-of-flight, determining pulse position, determining phase offset, and determining distance ([0046-0048], [0068-0072]; Figs. 1, 3, 4; claims 1-2), wherein
at least one light pulse comprises laser light (Marra teaches that light transmitter 12 may be a laser light source (Fig. 1, [0045]).
Marra fails to explicitly teach the transmission unit comprises a resonator in which a laser medium and a birefringent optical element are arranged.
However, Zhang teaches inserting a birefringent quartz plate in a laser cavity to generate two orthogonally polarized beams with different frequencies (Fig. 1, abstract, col 2: line 65 to col 3: line 10; claim 1)). Zhang also teaches that the quartz crystal plate is a birefringent element producing different optical path lengths for different polarization directions, resulting in two wavelengths/two frequencies in the same laser cavity (Col 1: line 64 and col 2: line 5; claim 1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Marra’s laser-based transmission unit to use the dual-frequency birefringent laser cavity taught by Zhang because Marra teaches that high-frequency modulation improves distance-measurement accuracy, and Zhang teaches a known laser-cavity implementation that generates two orthogonally polarized different-frequency beams using an intracavity birefringent quartz plate, thereby providing a suitable dual-frequency laser source for Marra’s high-frequency modulated optical transmission.
Regarding claim 9, Marra in view of Zhang, teaches the measurement device according to claim 7, wherein the birefringent optical element comprises a material selected from the following group: Quartz, lithium niobate, lithium tantalate, magnesium fluoride (Zhang, teaches a birefringent quartz crystal plate inserted in the laser cavity (Figs. 1-3, claim 1. See also, the rejection of claim 7)).
Regarding claim 12, Marra in view of Zhang, teaches the measurement device according to claim 7, wherein the modulation frequency is adjusted by a thickness of the birefringent optical element and/or by an angle between an optical axis of the birefringent optical element and an optical axis of the resonator (Zhang teaches that the larger the angle between the crystalline axis of the quartz plate and the laser beam in the cavity, the larger the frequency difference, and the thicker the quartz crystal plate, the larger the frequency difference (Col 2: lines 15-24; claim 1). Zhang also teaches rotating the quartz crystal plate to change the angle and obtain varied frequency differences from tens of MHz to more than 1000 MHz (Col 3: lines 7-10). Zhang further recite varying the angle and thickness to vary the frequency difference (at least claims 3-5).).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Marra et in view of Zhang and Coleman et al. (US 8804787 B1, “Coleman”).
Regarding claim 8, Marra in view of Zhang, fails to explicitly teach the measurement device according to claim 7, wherein a spectral linewidth of the laser light is smaller than one tenth of the modulation frequency.
However, Coleman teaches narrow-linewidth semiconductor laser systems and expressly discloses linewidth narrowing to less than 10 kHz (Col 3: lines 23-27; Col 5: lines 46-50). As described above (see 112 rejection), if the modulation frequency is at least 500 MHz, one tenth is 50 MHz; a linewidth below 10 kHz is far smaller than one tenth of the modulation frequency.
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Marra’s laser-based transmission unit to use the narrow-linewidth semiconductor laser taught by Coleman. The reason for the modification is that Marra’s distance measurement relies on evaluating the phase offset of a high-frequency modulated optical pulse, and a narrow-linewidth laser provides improved spectral purity and reduced optical frequency/phase noise, which would predictably improve the stability of the transmitted modulated optical signal and support more accurate phase-based distance refinement.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Marra et in view of Zhang and Bondu.
Regarding claim 10, Marra in view of Zhang, fails to explicitly teach the measurement device according to claim 7, wherein the birefringent optical element is an electro-optical element.
However, Bondu teaches that a birefringent electro-optical element may be inserted into the cavity and adjusted by electrical voltage, where the voltage changes the refractive index and optical path for one polarization ([0067]).
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify the Marra to use Bondu’s birefringent electro-optical element as the birefringent optical element. Doing so would have predictably provided electrical tunability of the frequency difference while retaining the dual-frequency birefringent laser structure used to generate the modulated optical transmission signal.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Marra et in view of Zhang and Daniel (US 6574256 B1, “Daniel”).
Regarding claim 11, Marra in view of Zhang, fails to explicitly teach the measurement device according to claim 7, wherein the laser medium comprises a semiconductor layer sequence with an active layer for generating laser light, wherein the active layer is periodically structured and forms an interference filter.
However, Daniel teaches a distributed feedback semiconductor laser including a semiconductor layer sequence having a substrate, buffer layer, cladding layers, confinement layers, and an active region/active layer. Daniel further teaches that active region 110 includes InGaN multiple quantum well layers and that a periodically corrugated grating is etched into the active region to form grating teeth (Claims 1, 4; Col 3: line 44 to col 4: line 12). The grating period is selected relative to the emission wavelength, and the grating couples backward and forward traveling waves to provide distributed optical feedback (Col 4: line 65 to col 5: line 5). Thus, Daniel teaches a semiconductor laser medium having an active layer that is periodically structured and functions as a wavelength-selective DFB/interference filter.
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify the laser source used in the Marra- to include the laser medium as the semiconductor DFB active-layer structure taught by Daniel. The reason for the modification is that Marra uses a laser light source for optical distance measurement, and Daniel teaches a known semiconductor DFB laser implementation in which the active layer is periodically corrugated to provide distributed optical feedback and wavelength-selective laser emission. The modification would have predictably provided a compact semiconductor laser medium with a periodically structured active layer for stable, wavelength-selective laser operation.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Marra et in view of Zhang and De Mersseman.
Regarding claim 13, Marra in view of Zhang, fails to explicitly teach measurement device according to claim 7, wherein the evaluation unit is configured to determine a Doppler shift of the modulation frequency of the receiving signal.
De Mersseman teaches that moving objects result in variable-amplitude range-bin pulses, which enable Doppler frequency measurement via spectral resolution ([0060-0061]). De Mersseman further teaches two-dimensional FFT processing for Doppler frequency detection and extraction of object relative velocity related to Doppler frequency [0076], [0081-0083]. See also, Figs. 16-17.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further configure Marra’s modulated LiDAR receiver to determine velocity from Doppler shift as taught by De Mersseman, because Marra already uses high-frequency optical modulation and received phase/time-of-flight information for distance measurement, and De Mersseman teaches that Doppler processing of modulated LiDAR signals provides target velocity information
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Noguchi et al. (US 11719817 B2), Distance-measuring Apparatus and Control Method
Bretenaker et al. (US 5091912 A), teaches Laser Having Two Modes at Different Frequencies
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/JEMPSON NOEL/Examiner, Art Unit 3645
/YUQING XIAO/Supervisory Patent Examiner, Art Unit 3645
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