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 06/26/2024. Claims 1-12 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 statements submitted by Applicant are 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.
Drawings
The drawings are objected to because in Fig. 10 step S203 “IS OUTPUT OF OBJECT LIGHT LESS THAN OR EQUAL TO EYE-SAFE STANDARD” should be written “IS THE OUTPUT OF THE IRRADIATION LIGHT LESS THAN OR EQUAL TO THE EYE-SAFE STANDARD” as described in paragraph [0090] of the specification.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Specification
The specification is objected to because of the following informalities:
"In paragraph [0079] lines 10 and 13, “optical circulator 34” should be replaced by “third beam splitter 32c”
Appropriate correction is required.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 5 and 11 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1 and 7 of copending Application No. 18/882,812 in view of Haraguchi et al. (US 20210141067 A1) and Timothy C. Munks (US 6587214 B1).
Regarding Claims 5 and 7, a comparison of limitations is shown with reference to claim 1 of 18/882,812 (the difference is in the bold text).
Instant application 18/755,623
Application 18/882,812
Claim 5 A measurement device comprising
Claim 1 A measurement device comprising:
a light source;
a light source that emits light;
an interference optical system that separates light from the light source into reference light and irradiation light for irradiating an object and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere with each other to generate interference light;
an interference optical system including a beam splitter that splits the light emitted from the light source into reference light and irradiation light for irradiating an object, the interference optical system generating interference light by causing reflected light generated by at least part of the irradiation light being reflected by the object and the reference light to interfere with each other;
at least one optical element that emits the at least part of the irradiation light and receives the reflected light;
at least one optical element that emits the at least part of the irradiation light;
a photodetector that detects the interference light;
a first photodetector that detects the interference light;
and another photodetector,
a second photodetector that detects monitoring light that is any one of part of the light emitted from the light source, part of the irradiation light in the interference optical system, and part of the reference light in the interference optical system;
wherein the interference optical system includes a beam splitter having a first terminal to which the light from the light source is input, a second terminal from which the reference light is output, and a third terminal from which the irradiation light is output, the other photodetector detects part of the irradiation light from the third terminal of the beam splitter to the optical element,
and a processing circuit that adjusts an intensity of the irradiation light to be emitted to an outside according to an intensity of the monitoring light, wherein the interference optical system further includes a circulator connected to the beam splitter and the at least one optical element.
and the measurement device satisfies relationships of
[Math.1]
d1≤ D (D = d2 + d3) (1)
[Math.3]
|D-d1| ≥ |d’-d1| (D’ = d5 + d6) (3)
where
d1 is an optical path length of a first path extending from the second terminal of the beam splitter to the photodetector,
d2 is an optical path length of a second path extending from the third terminal of the beam splitter to the optical element,
d3 is an optical path length of a third path extending from the optical element to the photodetector,
d5 is an optical path length of a fifth path extending from the third terminal of the beam splitter to the other photodetector, and
d6 is an optical path length of a sixth path extending from the other photodetector to the photodetector.
Claim 7 The measurement device according to claim 1, wherein the at least one optical element receives the reflected light and inputs the reflected light to the interference optical system.
Claim 11 A measurement device comprising
a light source;
an interference optical system that separates light from the light source into reference light and irradiation light for irradiating an object and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere with each other to generate interference light;
at least one optical element that emits the at least part of the irradiation light and receives the reflected light;
a photodetector that detects the interference light;
another photodetector that detects part of the irradiation light from the interference optical system to the optical element,
[Math.5]
f1≥f3 (5)
where
f1 is a beat frequency caused by interference between the reference light and, of the irradiation light, light reflected by the optical element and reaching the photodetector, and
f3 is a beat frequency caused by interference between the reference light and, of the irradiation light, light leaving the other photodetector and reaching the photodetector.
Regarding claim 5, Haraguchi teaches the interference optical system includes a beam splitter (Fig. 1; [0019], optical coupler 2 is identified as an optical splitter.) having a first terminal (Fig. 1; [0019], Coupler 2 receives light directly from reference light source 1) to which the light from the light source is input, a second terminal (Fig. 1; [0019], [0021], One output of coupler 2 feeds local oscillator light path 50) from which the reference light is output, and a third terminal (Fig. 1; [0019], [0021], The other output of coupler 2 feeds the signal light branch through semiconductor optical amplifier 3, amplifier 4, and circulator 5 to antenna 6.) from which the irradiation light is output, and
the measurement device satisfies relationships of
[Math.1]
d1≤ D (D = d2 + d3) (1) (See below)
[Math.2]
|D-d1| ≥ |d4-d1| (2)
where
d1 (Fig. 1, d1=LL) is an optical path length of a first path extending from the second terminal of the beam splitter to the photodetector (Haraguchi’s local oscillator light travels from the local oscillator output of coupler 2, through local oscillator path 50 and combining coupler 8, to balanced receiver 9. Haraguchi defines LL as the local oscillator optical path length extending from coupler 2 to balanced receiver 9.),
d2 is an optical path length of a second path extending from the third terminal of the beam splitter to the optical element (Haraguchi’s Fig.1 corresponding path extends: coupler 2→SOA 3→amplifier 4→circulator 5→antenna 6. This is the signal light path from the signal output of coupler 2 to optical antenna 6.),
d3 (Haraguchi’s Fig.1 corresponding path extends: antenna 6→circulator 5→reception path 51→path adjustment unit 7→combining coupler 8→receiver 9. Haraguchi teaches that light received by antenna 6 is routed by circulator 5 into reception path 51, combined with local oscillator light at coupler 8, and received by balanced receiver 9.) is an optical path length of a third path extending from the optical element to the photodetector (Haraguchi defines the signal light path length LS as the path extending from coupler 2 to balanced receiver 9 for light internally scattered at optical antenna 6. That path necessarily includes: the outward path from coupler 2 to antenna 6; and the return path from antenna 6 to receiver 9. Therefore: D=d2+d3=LS. Haraguchi states that LS and LL are measured from coupler 2 to balanced receiver 9 (See [0023]).), and
d4 is an optical path length of a fourth path extending from the third terminal of the beam splitter to the photodetector via a noise light path inside the interference optical system (Haraguchi teaches leakage light from optical circulator 5 entering balanced receiver 9. The complete route is: signal output of coupler 2→SOA 3→amplifier 4→circulator 5 leakage→reception path 51→coupler 8→receiver 9. Haraguchi states that internal scattering from antenna 6 or leakage from circulator 5 enters balanced receiver 9 after delay TS, where: TS=LS/c. Thus, Haraguchi assigns the circulator leakage path the path delay associated with LS: D4=LS. See Fig. 4(d), 4(f), and [0026]- [0027].).
So, for the mathematical relationships above:
d1≤D
Haraguchi teaches: LS>LL. Because: d1=LL and: D=LS, then: d1<D, which satisfies: d1≤D. The LS>LL relationship and the definitions of those path lengths appear in [0022]- [0023].
∣D−d1∣≥∣d4−d1∣
Under Haraguchi’s disclosed path delay relationship: D=LS and: d4=LS. Therefore: D=d4, and: ∣D- d1∣=∣d4−d1∣ satisfies ∣D- d1∣≥ ∣d4-d1∣.
Haraguchi fails to explicitly teach
another photodetector
the other photodetector detects part of the irradiation light from the third terminal of the beam splitter to the optical element, and
[Math.3]
|D-d1| ≥ |d’-d1| (D’ = d5 + d6) (3)
where
d5 is an optical path length of a fifth path extending from the third terminal of the beam splitter to the other photodetector, and
d6 is an optical path length of a sixth path extending from the other photodetector to the photodetector.
However, Yamashita teaches first branching coupler 30 dividing source light into measurement and reference light and second branching coupler 200 positioned in the measurement light path. Coupler 200 divides the measurement light into actual measurement light and monitor light and directs the monitor light to optical power monitor 210 ([0019]- [0021], monitor 210 is the other photodetector).
It would have been obvious to one of ordinary skill in the art before the effective filing date to include another photodetector, as taught by Yamashita, to detect a portion of the measurement or irradiation light, because Yamashita teaches that monitor 210 measures light divided by monitoring coupler 200 and supplies the measured intensity information for determining and controlling the actual irradiation power. Such monitoring permits the emitted measurement light to be maintained at an appropriate level, thereby improving measurement reliability and preventing excessive illumination of the object.
Haraguchi, in view of Yamashita, teaches the other photodetector detects part of the irradiation light from the third terminal of the beam splitter to the optical element (Haraguchi [0021] teaches the path: coupler 2 signal output→ amplifiers 3,4→ circulator 5→antenna 6. Yamashita [0015] teaches that measurement light from first branching coupler 30 passes through monitoring branching coupler 200 toward the sample side optical system. Yamashita [0019] further teaches that coupler 200 divides this measurement light into actual measurement light and monitor light supplied to monitor 210. Accordingly, in the combined device, monitor 210 detects part of the irradiation light traveling: from the third terminal of Haraguchi coupler 2→ toward optical antenna 6. So, d5=coupler 2 signal output→ amplifiers 3,4→ circulator 5→ coupler 200→ monitor detector 210.).
It would have been obvious to modify Haraguchi, as taught by Yamashita, by placing Yamashita’s monitoring coupler 200 and monitor photodetector 210 in Haraguchi’s signal light path downstream of the signal light output of optical coupler 2 and upstream of optical antenna 6. Haraguchi teaches that the signal light output from coupler 2 travels through amplifiers 3 and 4 and circulator 5 toward optical antenna 6, while Yamashita teaches positioning a monitoring coupler in the measurement light path after the measurement/reference splitter and directing a portion of that measurement light to monitor 210. The modification would permit the power of the irradiation light actually traveling toward antenna 6 to be measured and controlled, thereby improving the accuracy, stability, and safety of the measurement.
Accordingly, d5 is an optical path length of a fifth path extending from the third terminal of the beam splitter to the other photodetector (See the rejection above, d5=coupler 2 signal output→ amplifiers 3,4→ circulator 5→ coupler 200→ monitor detector 210.).
Haraguchi, in view of Yamashita, still fails to explicit d6 is an optical path length of a sixth path extending from the other photodetector to the photodetector.
However, Munks teaches that light incident on a photodetector may be reflected from the photodetector and detected by another photodetector. In particular, Munks teaches that second photodiode 54 may include an anti-reflection coating on incident surface 56 to reduce reflections that otherwise can be detected by first photodiode 44 and result in erroneous signals. See Munks, col. 5, ll. 4-12 and Fig. 3.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify the Haraguchi measurement device, as taught by Munks, by accounting for light reflected from the incident surface of monitoring photodetector 210 and routed to balanced receiver 9. Haraguchi recognizes that internally scattered light from optical antenna 6 and leakage light from circulator 5 can enter balanced receiver 9, and therefore treats internal optical reflections and leakage as signals that must be managed within the coherent receiver. Munks further teaches that reflections from second photodiode 54 can be detected by first photodiode 44 and can produce erroneous signals. See Munks, col. 5, ll. 4-12, Fig. 3. A skilled artisan therefore would have recognized reflection from Yamashita’s added monitor photodetector as another predictable internal noise source and would have configured its optical return path so that it does not produce a separate later false return signal within the usable measurement region, thereby improving measurement reliability. Accordingly: D′=d5+d6 is the complete parasitic round-trip path from the signal output of coupler 2 to monitor detector 210 and from detector 210 to receiver 9.
As described above, Haraguchi, in view of Yamashita, discloses that the light reflected from monitoring photodetector 210 travels through monitoring coupler 200, circulator 5, reception path 51, and combining coupler 8 to balanced receiver 9. Let A be the common path from coupler 2 to monitoring coupler 200, B be the path from coupler 200 to antenna 6, M be the path from coupler 200 to monitor 210, and R be the common return path from coupler 200 to receiver 9. The optical element reflection path is D =A+2B+R, while the monitor detector reflection path is D′=A+2M+R. It would have been obvious to select equal optical branch lengths M=B, thereby causing the monitor reflection signal to occur at the same optical delay as Haraguchi’s antenna internal reflection signal rather than at a separate false measurement position. Consequently, D′=D, such that ∣D−d1∣=∣D′−d1∣, and the equality satisfies the claimed relationship ∣D−d1∣≥∣D′−d1∣.
For claim 11, similar analysis can be made to show the instant claim is obvious variations of claim 1, with references cited in the prior art rejections below. In the interest of brevity, please see rejections in the prior art section.
Regarding claim 11, Haraguchi teaches a measurement device (Fig. 1, [0018]- [0019] Laser radar system 100 measures distance to target 20 or movement characteristics of target 20.) comprising:
a light source (Fig. 1; [0019]- [0020], Reference light source 1 emits polarized light and is frequency modulated by injection-current control signal 14.);
an interference optical system (Fig. 1; [0019]-[0020], optical coupler 2, optical circulator 5, optical combining coupler 8 ) that separates light from the light source into reference light and irradiation light (Fig. 1; [0021], optical coupler 2 splits light from source 1 into a local oscillator light path 50 and a signal light path.) for irradiating an object (Fig. 1; [0021]- [0022], Signal light is amplified, passes through circulator 5, and is emitted into space by optical antenna 6 toward target 20) and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere (Fig. 1; [0019], [0022], [0024], Light emitted by antenna 6 is scattered by target 20, routed by circulator 5 into reception path 51, and combined with local oscillator light at optical combining coupler 8.) with each other to generate interference light ([0019], [0024], Coupler 8 combines the local oscillator light and reception light, and balanced receiver 9 performs heterodyne detection on the combined optical signals.);
at least one optical element that emits the at least part of the irradiation light and receives the reflected light (Fig. 1; [0019], [0022], Optical antenna 6 emits the signal light into space and receives scattered light from target 20.); and
a photodetector ([0019], [0024] Balanced receiver 9 receives the combined optical signals and converts them into electrical signals. Haraguchi states that receiver 9 may include two photodiodes or a single photodiode.),
where
f1 is a beat frequency caused by interference between the reference light and, of the irradiation light, light reflected by the optical element and reaching the photodetector, and
Haraguchi further teaches the claimed relationship f1≥f2. In particular, Haraguchi teaches that internal scattering light from optical antenna 6 or leakage light from optical circulator 5 enters balanced receiver 9. See [0027], [0036]. Haraguchi further teaches that, during the time region in which the internally scattered signal light is detected, the signal light has first optical frequency f1, while the local oscillator light has second optical frequency f0, and the resulting receiver signal is obtained through heterodyne detection. See [0030]. Accordingly, the beat frequency produced by interference between local oscillator light and light internally scattered by optical antenna 6 is ∣f1- f0∣.
Haraguchi fails to explicitly teach another photodetector that detects part of the irradiation light from the interference optical system to the optical element,
wherein the measurement device satisfies a relationship of
[Math.5]
f1≥f3 (5)
where
f3 is a beat frequency caused by interference between the reference light and, of the irradiation light, light leaving the other photodetector and reaching the photodetector.
Haraguchi teaches that optical coupler 2 separates source light into local oscillator light and signal light, and that the signal light travels through amplifiers 3 and 4 and optical circulator 5 toward optical antenna 6. See Haraguchi [0019] and [0021]. Haraguchi does not explicitly teach another photodetector that detects part of the signal light traveling toward antenna 6. Yamashita teaches first branching coupler 30 separating source light into measurement light and reference light, monitoring branching coupler 200 positioned downstream of coupler 30 in the measurement light path, and measurement light monitor 210 receiving and detecting monitoring light divided from the measurement light by coupler 200. See Yamashita [0015] and [0019].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Haraguchi, as taught by Yamashita, by providing a monitoring branching coupler and another photodetector in Haraguchi’s outgoing signal light path between optical circulator 5 and optical antenna 6, such that the monitoring branching coupler passes a principal portion of the signal light toward optical antenna 6 and directs another portion of the same signal light to the monitoring photodetector. Haraguchi teaches that the signal light travels from optical coupler 2 through amplifiers 3 and 4 and circulator 5 toward optical antenna 6. Yamashita teaches positioning monitoring branching coupler 200 downstream of first branching coupler 30 in the measurement light path, dividing the measurement light into actual measurement light and monitoring light, and directing the monitoring light to measurement light monitor 210. A skilled artisan would have made the modification to measure the power of the irradiation light actually traveling toward the optical antenna, thereby permitting the irradiation level to be determined and controlled for reliable measurement and safe illumination of the object. Yamashita specifically teaches using the detected monitoring light intensity and the known splitting ratio to determine and control the amount of measurement light delivered toward the object.
Accordingly, Haraguchi, in view of Yamashita, teaches that the other photodetector detects part of the irradiation light from the interference optical system to the optical element.
Haraguchi, in view of Yamashita, still fails to explicit f3 is a beat frequency caused by interference between the reference light and, of the irradiation light, light leaving the other photodetector and reaching the photodetector.
However, Munks teaches that light incident on a photodetector may be reflected from the photodetector and detected by another photodetector. In particular, Munks teaches that second photodiode 54 may include an anti-reflection coating on incident surface 56 to reduce reflections that otherwise can be detected by first photodiode 44 and result in erroneous signals. See Munks, col. 5, ll. 4-12 and Fig. 3.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify the Haraguchi measurement device, as taught by Munks, by accounting for light reflected from the incident surface of monitoring photodetector 210 and routed to balanced receiver 9. Haraguchi recognizes that internally scattered light from optical antenna 6 and leakage light from circulator 5 can enter balanced receiver 9, and therefore treats internal optical reflections and leakage as signals that must be managed within the coherent receiver. Munks further teaches that reflections from second photodiode 54 can be detected by first photodiode 44 and can produce erroneous signals. See Munks, col. 5, ll. 4-12, Fig. 3. A skilled artisan therefore would have recognized reflection from Yamashita’s added monitor photodetector as another predictable internal noise source and would have configured its optical return path so that it does not produce a separate later false return signal within the usable measurement region, thereby improving measurement reliability.
Haraguchi teaches that internally scattered irradiation light from optical antenna 6 reaches balanced receiver 9 during time region with first optical frequency f1, while the local oscillator light has second optical frequency f0. Accordingly, the claimed first beat frequency is BF1=∣f1−f0∣ (See rejection of claim 7). Munks teaches that light reflected from second photodiode 54 may be detected by first photodiode 44 and may produce an erroneous signal. See Munks, col. 5, ll. 4-12. In the modified device, the irradiation light reflected from the monitoring photodetector retains optical frequency f1 and reaches balanced receiver 9, where it interferes with the same local oscillator light having optical frequency f0. The monitor reflection path is configured to have the same optical delay as the antenna internal reflection path, such that both reflected signals reach receiver 9 during the same frequency interval. Therefore, the third beat frequency is BF3=∣f1−f0∣=BF1, and the equality satisfies the claimed relationship f1≥f3.
A skilled artisan therefore would have configured the monitor detector reflection path to have the same optical delay as the antenna internal reflection path so that the monitor reflection signal appears at the same already accounted for beat frequency, rather than creating a separate false frequency peak within the usable measurement range.
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 9 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim 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.
Claim 9 recites that “the interference optical system includes another beam splitter” and subsequently refers to “the other beam splitter.” However, independent claim 7, from which claim 9 depends, does not previously recite a beam splitter relative to which the claimed beam splitter would be “another” beam splitter. It is therefore unclear whether the limitation refers to an additional beam splitter distinct from an unstated first beam splitter or merely introduces a single beam splitter.
For purposes of examination, “another beam splitter” is interpreted as “a beam splitter”, “the other beam splitter” is interpreted as “the beam splitter”, and inputs the reference light to the photodetector instead of another beam splitter, the other beam splitter, and inputs the reflected light to the photodetector
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.
Claims 1-2, 6-8, 12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Haraguchi et al. (US 20210141067 A1, “Haraguchi”).
Regarding claim 1, Haraguchi teaches a measurement device (Fig. 1, [0018]- [0019] Laser radar system 100 measures distance to target 20 or movement characteristics of target 20.) comprising:
a light source (Fig. 1; [0019]- [0020], Reference light source 1 emits polarized light and is frequency modulated by injection-current control signal 14.);
an interference optical system (Fig. 1; [0019]-[0020], optical coupler 2, optical circulator 5, optical combining coupler 8 ) that separates light from the light source into reference light and irradiation light (Fig. 1; [0021], optical coupler 2 splits light from source 1 into a local oscillator light path 50 and a signal light path.) for irradiating an object (Fig. 1; [0021]- [0022], Signal light is amplified, passes through circulator 5, and is emitted into space by optical antenna 6 toward target 20) and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere (Fig. 1; [0019], [0022], [0024], Light emitted by antenna 6 is scattered by target 20, routed by circulator 5 into reception path 51, and combined with local oscillator light at optical combining coupler 8.) with each other to generate interference light ([0019], [0024], Coupler 8 combines the local oscillator light and reception light, and balanced receiver 9 performs heterodyne detection on the combined optical signals.);
at least one optical element that emits the at least part of the irradiation light and receives the reflected light (Fig. 1; [0019], [0022], Optical antenna 6 emits the signal light into space and receives scattered light from target 20.); and
a photodetector ([0019], [0024] Balanced receiver 9 receives the combined optical signals and converts them into electrical signals. Haraguchi states that receiver 9 may include two photodiodes or a single photodiode.), wherein
the interference optical system includes a beam splitter (Fig. 1; [0019], optical coupler 2 is identified as an optical splitter.) having a first terminal (Fig. 1; [0019], Coupler 2 receives light directly from reference light source 1) to which the light from the light source is input, a second terminal (Fig. 1; [0019], [0021], One output of coupler 2 feeds local oscillator light path 50) from which the reference light is output, and a third terminal (Fig. 1; [0019], [0021], The other output of coupler 2 feeds the signal light branch through semiconductor optical amplifier 3, amplifier 4, and circulator 5 to antenna 6.) from which the irradiation light is output, and
the measurement device satisfies relationships of
[Math.1]
d1≤ D (D = d2 + d3) (1) (See below)
[Math.2]
|D-d1| ≥ |d4-d1| (2)
where
d1 (Fig. 1, d1=LL) is an optical path length of a first path extending from the second terminal of the beam splitter to the photodetector (Haraguchi’s local oscillator light travels from the local oscillator output of coupler 2, through local oscillator path 50 and combining coupler 8, to balanced receiver 9. Haraguchi defines LL as the local oscillator optical path length extending from coupler 2 to balanced receiver 9.),
d2 is an optical path length of a second path extending from the third terminal of the beam splitter to the optical element (Haraguchi’s Fig.1 corresponding path extends: coupler 2→SOA 3→amplifier 4→circulator 5→antenna 6. This is the signal light path from the signal output of coupler 2 to optical antenna 6.),
d3 (Haraguchi’s Fig.1 corresponding path extends: antenna 6→circulator 5→reception path 51→path adjustment unit 7→combining coupler 8→receiver 9. Haraguchi teaches that light received by antenna 6 is routed by circulator 5 into reception path 51, combined with local oscillator light at coupler 8, and received by balanced receiver 9.) is an optical path length of a third path extending from the optical element to the photodetector (Haraguchi defines the signal light path length LS as the path extending from coupler 2 to balanced receiver 9 for light internally scattered at optical antenna 6. That path necessarily includes: the outward path from coupler 2 to antenna 6; and the return path from antenna 6 to receiver 9. Therefore: D=d2+d3=LS. Haraguchi states that LS and LL are measured from coupler 2 to balanced receiver 9 (See [0023]).), and
d4 is an optical path length of a fourth path extending from the third terminal of the beam splitter to the photodetector via a noise light path inside the interference optical system (Haraguchi teaches leakage light from optical circulator 5 entering balanced receiver 9. The complete route is: signal output of coupler 2→SOA 3→amplifier 4→circulator 5 leakage→reception path 51→coupler 8→receiver 9. Haraguchi states that internal scattering from antenna 6 or leakage from circulator 5 enters balanced receiver 9 after delay TS, where: TS=LS/c. Thus, Haraguchi assigns the circulator leakage path the path delay associated with LS: D4=LS. See Fig. 4(d), 4(f), and [0026]- [0027].).
So, for the mathematical relationships above:
d1≤D
Haraguchi teaches: LS>LL. Because: d1=LL and: D=LS, then: d1<D, which satisfies: d1≤D. The LS>LL relationship and the definitions of those path lengths appear in [0022]- [0023].
∣D−d1∣≥∣d4−d1∣
Under Haraguchi’s disclosed path delay relationship: D=LS and: d4=LS. Therefore: D=d4, and: ∣D−d1∣=∣d4−d1∣ satisfies ∣D−d1∣≥ ∣d4−d1∣.
Regarding claim 2, Haraguchi teaches the measurement device according to claim 1, wherein
the interference optical system includes an optical circulator (Fig. 1; [0019], Haraguchi includes optical circulator 5 in the signal and reception optical system.),
the optical circulator is connected to the third terminal of the beam splitter (Fig. 1; [0019], [0021], the signal light output of coupler 2 passes through SOA 3 and amplifier 4 to circulator 5.) and the at least one optical element (Fig. 1; [0019], [0021]- [0022], Circulator 5 routes outgoing signal light to optical antenna 6 and routes received light from antenna 6 into reception path 51.),
the photodetector is connected to the second terminal of the beam splitter (Fig. 1; [0019], The local oscillator output of coupler 2 is connected through local oscillator path 50 and combining coupler 8 to balanced receiver 9.) and the optical circulator (Fig. 1; [0019], Circulator 5 is connected through reception path 51, path length adjustment unit 7, and combining coupler 8 to balanced receiver 9.), and
the noise light path is a path passing through the optical circulator (Fig. 4(d), 4(f); [0026]- [0027], Haraguchi identifies leakage light from optical circulator 5 that enters balanced receiver 9.).
Regarding claim 6, Haraguchi teaches the measurement device according to claim 1, further comprising a processing circuit (Fig. 1, a measurement unit 30) that processes a signal output from the photodetector (Fig. 1, [0019], a balanced receiver 9 to receive the combined optical signals and convert them into electric signals; and a measurement unit 30 to use the photo electrically converted reception signals to measure the distance to the target 20 or movement characteristics of the target 20.),
wherein the light source is capable of changing a frequency of the light ([0020], In accordance with the injection-current control signal 14 controlled in a burst pulse manner, the reference light source 1 outputs, during a pulse-ON period, light whose frequency is a first frequency f1, and the reference light source 1 outputs, during a pulse-OFF period, light whose frequency is a second frequency f0).
Regarding claim 7, Haraguchi teaches a measurement device (Fig. 1, [0018]- [0019] Laser radar system 100 measures distance to target 20 or movement characteristics of target 20.) comprising:
a light source (Fig. 1; [0019]- [0020], Reference light source 1 emits polarized light and is frequency modulated by injection-current control signal 14.);
an interference optical system (Fig. 1; [0019]-[0020], optical coupler 2, optical circulator 5, optical combining coupler 8 ) that separates light from the light source into reference light and irradiation light (Fig. 1; [0021], optical coupler 2 splits light from source 1 into a local oscillator light path 50 and a signal light path.) for irradiating an object (Fig. 1; [0021]- [0022], Signal light is amplified, passes through circulator 5, and is emitted into space by optical antenna 6 toward target 20) and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere (Fig. 1; [0019], [0022], [0024], Light emitted by antenna 6 is scattered by target 20, routed by circulator 5 into reception path 51, and combined with local oscillator light at optical combining coupler 8.) with each other to generate interference light ([0019], [0024], Coupler 8 combines the local oscillator light and reception light, and balanced receiver 9 performs heterodyne detection on the combined optical signals.);
at least one optical element that emits the at least part of the irradiation light and receives the reflected light (Fig. 1; [0019], [0022], Optical antenna 6 emits the signal light into space and receives scattered light from target 20.); and
a photodetector ([0019], [0024] Balanced receiver 9 receives the combined optical signals and converts them into electrical signals. Haraguchi states that receiver 9 may include two photodiodes or a single photodiode.),
wherein the measurement device satisfies a relationship of
[Math.4]
f1 ≥ f2 (4)
where
f1 is a beat frequency caused by interference between the reference light and, of the irradiation light, light reflected by the optical element and reaching the photodetector, and
f2 is a beat frequency caused by interference between the reference light and, of the irradiation light, light passing through a noise light path inside the interference optical system and reaching the photodetector.
Haraguchi further teaches the claimed relationship f1≥f2. In particular, Haraguchi teaches that internal scattering light from optical antenna 6 or leakage light from optical circulator 5 enters balanced receiver 9. See [0027], [0036]. Haraguchi further teaches that, during the time region in which the internally scattered signal light is detected, the signal light has first optical frequency f1, while the local oscillator light has second optical frequency f0, and the resulting receiver signal is obtained through heterodyne detection. See [0030]. Accordingly, the beat frequency produced by interference between local oscillator light and light internally scattered by optical antenna 6 is ∣f1- f0∣. The leakage light from circulator 5 is likewise a portion of the signal light having optical frequency f1 and is detected using the same local oscillator light having optical frequency f0; therefore, its beat frequency is also ∣f1-f0∣. Thus, the two claimed beat frequencies are equal, which satisfies f1≥f2.
Regarding claim 8, Haraguchi teaches the measurement device according to claim 7, wherein
the interference optical system includes an optical circulator (Fig. 1; [0019], Haraguchi includes optical circulator 5 in the signal and reception optical system.) that inputs the at least part of the irradiation light to the at least one optical element (Fig. 1; [0021], Signal light from coupler 2 passes through amplifiers 3 and 4 to circulator 5. Circulator 5 directs that signal light to optical antenna 6, which emits the light into space.) and inputs the reflected light to the photodetector (Fig. 1; [0022]- [0023], Light received by antenna 6 is separated from the outgoing signal path by circulator 5 and routed through reception path 51 and coupler 8 to balanced receiver 9.), and
the noise light path is a path passing through the optical circulator (Fig. 4(d), 4(f); [0026]- [0027], Haraguchi identifies leakage light from optical circulator 5 that enters balanced receiver 9.).
Regarding claim 12, Haraguchi teaches the measurement device according to claim 7, further comprising a processing circuit that processes (Fig. 1, a measurement unit 30) that processes a signal output from the photodetector (Fig. 1, [0019], a balanced receiver 9 to receive the combined optical signals and convert them into electric signals; and a measurement unit 30 to use the photo electrically converted reception signals to measure the distance to the target 20 or movement characteristics of the target 20.),
wherein the light source is capable of changing a frequency of the light ([0020], In accordance with the injection-current control signal 14 controlled in a burst pulse manner, the reference light source 1 outputs, during a pulse-ON period, light whose frequency is a first frequency f1, and the reference light source 1 outputs, during a pulse-OFF period, light whose frequency is a second frequency f0).
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 3 is rejected under 35 U.S.C. 103 as being unpatentable over Haraguchi in view of Risa Yamashita (JP 2017047061 A, “Yamashita”).
Regarding claim 3, Hamaguchi fails to explicitly teach the measurement device according to claim 1, wherein the interference optical system includes another beam splitter, the other beam splitter is connected to the third terminal of the beam splitter and the at least one optical element, the photodetector is connected to the second terminal of the beam splitter and the other beam splitter.
However, Yamashita teaches an optical interference measurement apparatus including first branching coupler 30, which divides source light into measurement light and reference light, and second branching coupler 200, which is positioned in the measurement light path and divides the measurement light into actual measurement light and monitor light. See Yamashita, claims 1- 2 and paragraphs [0015] and [0019]. Yamashita further teaches that reflected or scattered measurement light returns along the measurement path in the reverse direction and is combined with reference light for detection [0016], [0018].
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Haraguchi, as taught by Yamashita, by positioning a branching coupler in the irradiation light path between circulator 5 and optical antenna 6, because Yamashita teaches that the branching coupler permits a portion of the measurement light to be monitored so that the irradiation light power can be accurately controlled, thereby improving measurement reliability and preventing excessive irradiation power.
Haraguchi, in view of Yamashita, teaches the noise light path is a path passing through the other beam splitter (In combination with claim 1, Haraguchi teaches internally scattered light from optical antenna 6 entering receiver 9. In the modified device, this internally scattered noise light passes from antenna 6 through coupler 200 and circulator 5 to receiver 9, thereby teaching that the noise light path passes through the other beam splitter.).
Claims 4, 10 are rejected under 35 U.S.C. 103 as being unpatentable over Haraguchi in view of Risa Lin (US 20220196814 A1, “Lin”).
Regarding claim 4, Haraguchi fails to explicitly teach the measurement device according to claim 1, wherein the at least one optical element includes a plurality of optical elements, the plurality of optical elements each emitting part of the irradiation light, and the plurality of optical elements each satisfy the relationships of Formulas (1) and (2).
However, Lin teaches a coherent FMCW LiDAR transceiver having optical antenna arrays 110, each including a plurality of coherent pixels 118 and corresponding optical antennas 200. Optical splitter 112 distributes the input signal among N transmitter and receiver channels, thereby permitting concurrent transmission from the plurality of optical antennas. Lin further teaches that each optical antenna 200 emits its respective transmit signal into free space and reciprocally receives a reflected return signal from an object. See Lin, Figs. 1 and 2A–2D and at least [0052]- [0054], claim 1.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Haraguchi, as taught by Lin, by dividing the irradiation light among a plurality of substantially repeated transmit and receive channels, each terminating in a respective optical antenna, because Lin teaches that parallel optical channels permit range information to be acquired concurrently from multiple spatial locations ([0045], [0049]), thereby increasing measurement point rate, reducing scanning time, and expanding field of view coverage. A skilled artisan would have configured each repeated channel to retain Haraguchi’s relative reference light, optical element reflection, and internal noise path arrangement so that each antenna channel obtains the same separation of the desired and noise signals and the same reliable distance measurement operation. Accordingly, each optical element would satisfy the claimed path length relationships.
Regarding claim 10, Haraguchi fails to explicitly teach the measurement device according to claim 7, wherein the at least one optical element includes a plurality of optical elements, the plurality of optical elements each emitting part of the irradiation light, and the plurality of optical elements each satisfy the relationship of Formula (4).
However, Lin teaches a coherent FMCW LiDAR transceiver having optical antenna arrays 110, each including a plurality of coherent pixels 118 and corresponding optical antennas 200. Optical splitter 112 distributes the input signal among N transmitter and receiver channels, thereby permitting concurrent transmission from the plurality of optical antennas. Lin further teaches that each optical antenna 200 emits its respective transmit signal into free space and reciprocally receives a reflected return signal from an object. See Lin, Figs. 1 and 2A–2D and at least [0052]- [0054], claim 1.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Haraguchi, as taught by Lin, by dividing the irradiation light among a plurality of substantially identical transmit and receive channels, each including a respective optical antenna, because parallel antenna channels permit measurements at multiple spatial locations during the same measurement interval ([0045], [0049]), thereby increasing measurement point throughput and reducing the time required to scan a field of view. A skilled artisan would have predictably retained Haraguchi’s disclosed frequency relationship in each repeated channel so that, for every optical antenna, the beat frequency associated with light reflected by the antenna is at least as high as the beat frequency associated with internal noise light, thereby preventing the internal noise signal from limiting the usable measurement range of any channel.
Claims 5, 11 are rejected under 35 U.S.C. 103 as being unpatentable over Haraguchi in view of Yamashita and Timothy C. Munks (US 6587214 B1,” Munks”).
Regarding claim 5, Haraguchi teaches a measurement device (Fig. 1, [0018]- [0019] Laser radar system 100 measures distance to target 20 or movement characteristics of target 20.) comprising:
a light source (Fig. 1; [0019]- [0020], Reference light source 1 emits polarized light and is frequency modulated by injection-current control signal 14.);
an interference optical system (Fig. 1; [0019]-[0020], optical coupler 2, optical circulator 5, optical combining coupler 8 ) that separates light from the light source into reference light and irradiation light (Fig. 1; [0021], optical coupler 2 splits light from source 1 into a local oscillator light path 50 and a signal light path.) for irradiating an object (Fig. 1; [0021]- [0022], Signal light is amplified, passes through circulator 5, and is emitted into space by optical antenna 6 toward target 20) and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere (Fig. 1; [0019], [0022], [0024], Light emitted by antenna 6 is scattered by target 20, routed by circulator 5 into reception path 51, and combined with local oscillator light at optical combining coupler 8.) with each other to generate interference light ([0019], [0024], Coupler 8 combines the local oscillator light and reception light, and balanced receiver 9 performs heterodyne detection on the combined optical signals.);
at least one optical element that emits the at least part of the irradiation light and receives the reflected light (Fig. 1; [0019], [0022], Optical antenna 6 emits the signal light into space and receives scattered light from target 20.); and
a photodetector ([0019], [0024] Balanced receiver 9 receives the combined optical signals and converts them into electrical signals. Haraguchi states that receiver 9 may include two photodiodes or a single photodiode.), wherein
the interference optical system includes a beam splitter (Fig. 1; [0019], optical coupler 2 is identified as an optical splitter.) having a first terminal (Fig. 1; [0019], Coupler 2 receives light directly from reference light source 1) to which the light from the light source is input, a second terminal (Fig. 1; [0019], [0021], One output of coupler 2 feeds local oscillator light path 50) from which the reference light is output, and a third terminal (Fig. 1; [0019], [0021], The other output of coupler 2 feeds the signal light branch through semiconductor optical amplifier 3, amplifier 4, and circulator 5 to antenna 6.) from which the irradiation light is output, and
the measurement device satisfies relationships of
[Math.1]
Where
d1≤ D (D = d2 + d3) (1) (See the rejection of claim 1)
d1 is an optical path length of a first path extending from the second terminal of the beam splitter to the photodetector (See the rejection of claim 1),
d2 is an optical path length of a second path extending from the third terminal of the beam splitter to the optical element (See the rejection of claim 1),
d3 is an optical path length of a third path extending from the optical element to the photodetector (See the rejection of claim 1).
Haraguchi fails to explicitly teach another photodetector, the other photodetector detects part of the irradiation light from the third terminal of the beam splitter to the optical element,
the measurement device satisfies relationships of:
[Math.3]
|D-d1| ≥ |D’-d1| (D’ = d5 + d6) (3)
where
d5 is an optical path length of a fifth path extending from the third terminal of the beam splitter to the other photodetector, d6 is an optical path length of a sixth path extending from the other photodetector to the photodetector.
However, Yamashita teaches first branching coupler 30 dividing source light into measurement and reference light and second branching coupler 200 positioned in the measurement light path. Coupler 200 divides the measurement light into actual measurement light and monitor light and directs the monitor light to optical power monitor 210 ([0019]- [0021], monitor 210 is the other photodetector).
It would have been obvious to one of ordinary skill in the art before the effective filing date to include another photodetector, as taught by Yamashita, to detect a portion of the measurement or irradiation light, because Yamashita teaches that monitor 210 measures light divided by monitoring coupler 200 and supplies the measured intensity information for determining and controlling the actual irradiation power. Such monitoring permits the emitted measurement light to be maintained at an appropriate level, thereby improving measurement reliability and preventing excessive illumination of the object.
Haraguchi, in view of Yamashita, teaches the other photodetector detects part of the irradiation light from the third terminal of the beam splitter to the optical element (Haraguchi [0021] teaches the path: coupler 2 signal output→ amplifiers 3,4→ circulator 5→antenna 6. Yamashita [0015] teaches that measurement light from first branching coupler 30 passes through monitoring branching coupler 200 toward the sample side optical system. Yamashita [0019] further teaches that coupler 200 divides this measurement light into actual measurement light and monitor light supplied to monitor 210. Accordingly, in the combined device, monitor 210 detects part of the irradiation light traveling: from the third terminal of Haraguchi coupler 2→ toward optical antenna 6. So, d5=coupler 2 signal output→ amplifiers 3,4→ circulator 5→ coupler 200→ monitor detector 210.).
It would have been obvious to modify Haraguchi, as taught by Yamashita, by placing Yamashita’s monitoring coupler 200 and monitor photodetector 210 in Haraguchi’s signal light path downstream of the signal light output of optical coupler 2 and upstream of optical antenna 6. Haraguchi teaches that the signal light output from coupler 2 travels through amplifiers 3 and 4 and circulator 5 toward optical antenna 6, while Yamashita teaches positioning a monitoring coupler in the measurement light path after the measurement/reference splitter and directing a portion of that measurement light to monitor 210. The modification would permit the power of the irradiation light actually traveling toward antenna 6 to be measured and controlled, thereby improving the accuracy, stability, and safety of the measurement.
Accordingly, d5 is an optical path length of a fifth path extending from the third terminal of the beam splitter to the other photodetector (See the rejection above, d5=coupler 2 signal output→ amplifiers 3,4→ circulator 5→ coupler 200→ monitor detector 210.).
Haraguchi, in view of Yamashita, still fails to explicitly d6 is an optical path length of a sixth path extending from the other photodetector to the photodetector.
However, Munks teaches that light incident on a photodetector may be reflected from the photodetector and detected by another photodetector. In particular, Munks teaches that second photodiode 54 may include an anti-reflection coating on incident surface 56 to reduce reflections that otherwise can be detected by first photodiode 44 and result in erroneous signals. See Munks, col. 5, ll. 4-12 and Fig. 3.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify the Haraguchi measurement device, as taught by Munks, by accounting for light reflected from the incident surface of monitoring photodetector 210 and routed to balanced receiver 9. Haraguchi recognizes that internally scattered light from optical antenna 6 and leakage light from circulator 5 can enter balanced receiver 9, and therefore treats internal optical reflections and leakage as signals that must be managed within the coherent receiver. Munks further teaches that reflections from second photodiode 54 can be detected by first photodiode 44 and can produce erroneous signals. See Munks, col. 5, ll. 4-12, Fig. 3. A skilled artisan therefore would have recognized reflection from Yamashita’s added monitor photodetector as another predictable internal noise source and would have configured its optical return path so that it does not produce a separate later false return signal within the usable measurement region, thereby improving measurement reliability. Accordingly: D′=d5+d6 is the complete parasitic round-trip path from the signal output of coupler 2 to monitor detector 210 and from detector 210 to receiver 9.
As described above, Haraguchi, in view of Yamashita, discloses that the light reflected from monitoring photodetector 210 travels through monitoring coupler 200, circulator 5, reception path 51, and combining coupler 8 to balanced receiver 9. Let A be the common path from coupler 2 to monitoring coupler 200, B be the path from coupler 200 to antenna 6, M be the path from coupler 200 to monitor 210, and R be the common return path from coupler 200 to receiver 9. The optical element reflection path is D =A+2B+R, while the monitor detector reflection path is D′=A+2M+R. It would have been obvious to select equal optical branch lengths M=B, thereby causing the monitor reflection signal to occur at the same optical delay as Haraguchi’s antenna internal reflection signal rather than at a separate false measurement position. Consequently, D′=D, such that ∣D−d1∣=∣D′−d1∣, and the equality satisfies the claimed relationship ∣D−d1∣≥∣D′−d1∣.
Regarding claim 11, Haraguchi teaches a measurement device (Fig. 1, [0018]- [0019] Laser radar system 100 measures distance to target 20 or movement characteristics of target 20.) comprising:
a light source (Fig. 1; [0019]- [0020], Reference light source 1 emits polarized light and is frequency modulated by injection-current control signal 14.);
an interference optical system (Fig. 1; [0019]-[0020], optical coupler 2, optical circulator 5, optical combining coupler 8 ) that separates light from the light source into reference light and irradiation light (Fig. 1; [0021], optical coupler 2 splits light from source 1 into a local oscillator light path 50 and a signal light path.) for irradiating an object (Fig. 1; [0021]- [0022], Signal light is amplified, passes through circulator 5, and is emitted into space by optical antenna 6 toward target 20) and causes reflected light, generated by at least part of the irradiation light being reflected by the object, and the reference light to interfere (Fig. 1; [0019], [0022], [0024], Light emitted by antenna 6 is scattered by target 20, routed by circulator 5 into reception path 51, and combined with local oscillator light at optical combining coupler 8.) with each other to generate interference light ([0019], [0024], Coupler 8 combines the local oscillator light and reception light, and balanced receiver 9 performs heterodyne detection on the combined optical signals.);
at least one optical element that emits the at least part of the irradiation light and receives the reflected light (Fig. 1; [0019], [0022], Optical antenna 6 emits the signal light into space and receives scattered light from target 20.); and
a photodetector ([0019], [0024] Balanced receiver 9 receives the combined optical signals and converts them into electrical signals. Haraguchi states that receiver 9 may include two photodiodes or a single photodiode.),
where
f1 is a beat frequency caused by interference between the reference light and, of the irradiation light, light reflected by the optical element and reaching the photodetector (See the rejection of claim 7).
Haraguchi fails to explicitly teach another photodetector that detects part of the irradiation light from the interference optical system to the optical element,
wherein the measurement device satisfies a relationship of
[Math.5]
f1≥f3 (5)
where
f3 is a beat frequency caused by interference between the reference light and, of the irradiation light, light leaving the other photodetector and reaching the photodetector.
Haraguchi teaches that optical coupler 2 separates source light into local oscillator light and signal light, and that the signal light travels through amplifiers 3 and 4 and optical circulator 5 toward optical antenna 6. See Haraguchi [0019] and [0021]. Haraguchi does not explicitly teach another photodetector that detects part of the signal light traveling toward antenna 6. Yamashita teaches first branching coupler 30 separating source light into measurement light and reference light, monitoring branching coupler 200 positioned downstream of coupler 30 in the measurement light path, and measurement light monitor 210 receiving and detecting monitoring light divided from the measurement light by coupler 200. See Yamashita [0015] and [0019].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Haraguchi, as taught by Yamashita, by providing a monitoring branching coupler and another photodetector in Haraguchi’s outgoing signal light path between optical circulator 5 and optical antenna 6, such that the monitoring branching coupler passes a principal portion of the signal light toward optical antenna 6 and directs another portion of the same signal light to the monitoring photodetector. Haraguchi teaches that the signal light travels from optical coupler 2 through amplifiers 3 and 4 and circulator 5 toward optical antenna 6. Yamashita teaches positioning monitoring branching coupler 200 downstream of first branching coupler 30 in the measurement light path, dividing the measurement light into actual measurement light and monitoring light, and directing the monitoring light to measurement light monitor 210. A skilled artisan would have made the modification to measure the power of the irradiation light actually traveling toward the optical antenna, thereby permitting the irradiation level to be determined and controlled for reliable measurement and safe illumination of the object. Yamashita specifically teaches using the detected monitoring light intensity and the known splitting ratio to determine and control the amount of measurement light delivered toward the object.
Accordingly, Haraguchi, in view of Yamashita, teaches that the other photodetector detects part of the irradiation light from the interference optical system to the optical element.
Haraguchi, in view of Yamashita, still fails to explicit f3 is a beat frequency caused by interference between the reference light and, of the irradiation light, light leaving the other photodetector and reaching the photodetector.
However, Munks teaches that light incident on a photodetector may be reflected from the photodetector and detected by another photodetector. In particular, Munks teaches that second photodiode 54 may include an anti-reflection coating on incident surface 56 to reduce reflections that otherwise can be detected by first photodiode 44 and result in erroneous signals. See Munks, col. 5, ll. 4-12 and Fig. 3.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify the Haraguchi measurement device, as taught by Munks, by accounting for light reflected from the incident surface of monitoring photodetector 210 and routed to balanced receiver 9. Haraguchi recognizes that internally scattered light from optical antenna 6 and leakage light from circulator 5 can enter balanced receiver 9, and therefore treats internal optical reflections and leakage as signals that must be managed within the coherent receiver. Munks further teaches that reflections from second photodiode 54 can be detected by first photodiode 44 and can produce erroneous signals. See Munks, col. 5, ll. 4-12, Fig. 3. A skilled artisan therefore would have recognized reflection from Yamashita’s added monitor photodetector as another predictable internal noise source and would have configured its optical return path so that it does not produce a separate later false return signal within the usable measurement region, thereby improving measurement reliability.
Haraguchi teaches that internally scattered irradiation light from optical antenna 6 reaches balanced receiver 9 during time region with first optical frequency f1, while the local oscillator light has second optical frequency f0. Accordingly, the claimed first beat frequency is BF1=∣f1−f0∣ (See rejection of claim 7). Munks teaches that light reflected from second photodiode 54 may be detected by first photodiode 44 and may produce an erroneous signal. See Munks, col. 5, ll. 4-12. In the modified device, the irradiation light reflected from the monitoring photodetector retains optical frequency f1 and reaches balanced receiver 9, where it interferes with the same local oscillator light having optical frequency f0. The monitor reflection path is configured to have the same optical delay as the antenna internal reflection path, such that both reflected signals reach receiver 9 during the same frequency interval. Therefore, the third beat frequency is BF3=∣f1−f0∣=BF1, and the equality satisfies the claimed relationship f1≥f3.
A skilled artisan therefore would have configured the monitor detector reflection path to have the same optical delay as the antenna internal reflection path so that the monitor reflection signal appears at the same already accounted for beat frequency, rather than creating a separate false frequency peak within the usable measurement range.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Haraguchi in view of Hong et al. (US 20190123508 A1, “Hong”).
Regarding claim 9, Haraguchi teaches the measurement device according to claim 7, wherein
the interference optical system includes (a)[another] beam splitter (Fig. 1; [0019], optical coupler 2 is identified as an optical splitter),
the [other] beam splitter inputs the at least part of the irradiation light to the at least one optical element (Fig. 1, [0021]) and inputs the reflected light to the photodetector (Fig. 1, [0019], Haraguchi teaches that the local oscillator light travels through local oscillator path 50 to combining coupler 8 and balanced receiver 9. The local oscillator light is combined with reception light and detected by receiver 9.), and
Haraguchi fails to explicitly teach that the noise light path is a path passing through the [other] beam splitter.
However, Hong teaches a beam splitter 503 positioned in a common transmit and receive optical path. Beam splitter 503 permits the irradiation light from light source 501 to pass toward optical elements 511 and 512 and redirects returning reflected light toward receiving unit 502, which includes a detector. See Hong, Fig. 5 and [0071]. Hong further teaches that, in Fig. 5, transmitted LiDAR light may contaminate reception at the detector because part of the transmitted light may be scattered or reflected by optical elements, a glass cover, or sidewalls along the optical path and thereafter collected by the detector. See Hong [0097]- [0101]. Accordingly, the internally scattered or reflected portion of the irradiation light travels from the source through beam splitter 503 toward the optical components and returns through beam splitter 503 toward the detector. Hong therefore teaches that the noise light path is a path passing through the beam splitter.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Haraguchi, as taught by Hong, by replacing optical circulator 5 with a common transmit and receive beam splitter configured to direct irradiation light toward optical antenna 6 and direct returning reflected light toward balanced receiver 9. Hong teaches that such a monostatic beam splitter arrangement aligns the transmitting and receiving optical paths, provides a large usable optical aperture, and enables a compact LiDAR configuration.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Yokoyama et al. (US 20200198049 A1), teaches laser welding apparatus and laser welding method
Höller et al. (US 20220413098 A1), teaches fmcw lidar system and method for simultaneous range and velocity measurement
Xing Wei (US 20200225021 A1), teaches optical coherence tomography system
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JEMPSON NOEL whose telephone number is (571) 272-3376. The examiner can normally be reached on Monday-Friday 9:30-5:30.
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, Yuqing Xiao can be reached on (571) 270-3603. 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.
/JEMPSON NOEL/Examiner, Art Unit 3645
Prosecution Insights