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 .
Claims 1-19, 22 are currently pending and examined below.
Response to amendment
This is a final Office action in response to applicant's remarks/arguments filed on 04/23/2026.
Status of the claims:
Claims 1, 4. 7-10, 15 and 22 have been amended.
Applicant’s arguments, see Remarks pages 6-8, filed on 04/23/2026, with respect to the rejection(s) of claim(s) 1-19, 22 under 103 have been fully considered and are not persuasive. Therefore, the rejection is maintained.
Applicant argues that Ohtomo does not disclose “a first modulator configured to generate distance measurement light acquired by performing first modulation on light from the light source.” The amendment added this limitation to independent claims 1 and 22.
Applicant’s argument has been considered but is not persuasive. Ohtomo discloses light emitting element 1 as a light source and light emission driving circuit 12 as a first modulator. Ohtomo explains that light emission driving circuit 12 controls light emitting element 1 and causes the emitted laser light to be modulated at a predetermined frequency and projected as distance-measurement light 22. Accordingly, Ohtomo teaches generating distance measurement light by performing a first modulation on light from a light source, as recited in claim 1 (Fig. 3, para 52, 57).
Applicant argues that prism 55 merely reflects the already generated distance measurement light and therefore does not perform a second modulation.
Applicant’s argument does not account for amplitude filter 56. Ohtomo does not merely reflect an unchanged portion of distance-measurement light 22. Ohtomo provides amplitude filter 56 on the reflection surface of reference reflection prism 55. As distance-measurement light 22 traverses amplitude filter 56, the light amount of the resulting internal reference light 22″ is gradually changed. Thus, the reference reflection prism 55 and amplitude filter 56 collectively form a second optical modulator that generates internal reference light 22″ by performing an additional intensity modulation on light originating from light emitting element 1. Ohtomo teaches that filter 56 has continuously or gradually changing density, thereby continuously increasing or decreasing the transmitted light amount. The measurement light traverses the filter before being received as internal reference light 22″ (See Claims 2-4, 6-7; para 42- 43, 45, 59, 62, 67, 69).
Applicant argues that varying intensity through amplitude filter 56 is merely passive filtering rather than active modulation.
Applicant’s argument is not corresponding with the scope of claim 1. Claim 1 does not require the second modulator to be electrically controlled, active, programmable, or formed by a particular type of modulating device. The claim merely requires a second modulator configured to perform intensity modulation on light from the light source. Ohtomo’s amplitude filter 56 changes the intensity of the light passing through it and therefore performs intensity modulation under the broadest reasonable interpretation of the claim language (See Claims 2-4, 6-7; para 42- 43, 45, 59, 62, 67, 69).
Applicant indicates that Maleki’s beam splitter 108 divides the FM optical signal into two substantially identical branches and does not itself perform a separate second intensity modulation. Maleki describes splitting the FM signal into one branch directed toward the target path and another branch directed toward beam combiner 114.
Applicant’s discussion of Maleki does not identify an error in the rejection because Maleki is not relied upon to teach the claimed second intensity modulator. Ohtomo’s reference reflection prism 55 and amplitude filter 56 teach the second intensity modulation. Maleki is relied upon for teaching coherent interference or mixing of reflected measurement light with reference light at a photodetector.
Maleki teaches that beam combiner 114 combines the returned optical chirp with the LO reference chirp and that photodetector 120 coherently mixes the two signals (Para 121. See also, Claims 1, 5, 18).
Applicant characterizes the claim as requiring a “dual-modulator architecture” in which transmitted light and reference light originate from separate modulations of the same source.
Claim 1 does not require the first and second modulators to be arranged in parallel branches, to independently receive unmodulated light directly from the source, or to operate simultaneously. Nor does the claim exclude serial modulation. In Ohtomo, light emission driving circuit 12 performs the first modulation to generate distance measurement light 22. A portion of that same source light subsequently traverses amplitude filter 56 and is subjected to an additional intensity modulation before being received as internal reference light 22″. Accordingly, both modulations are performed on light originating from the same light source, as required by the claim.
Applicant argues that the additional references were not applied to cure the purported missing dual-modulator limitation.
This argument is not persuasive because no such deficiency remains in the Ohtomo Maleki combination. Ohtomo teaches both the first modulation and the second intensity modulation, while Maleki teaches the interference detector. Yamashita, Link, and Hartog are relied upon for the additional limitations of the respective dependent claims, not for the first and second modulator limitations of claim 1.
Applicant’s arguments concerning method claim 22 have been considered but are not persuasive for substantially the same reasons discussed above regarding claim 1. Ohtomo teaches generating distance-measurement light by first modulating light emitted from light emitting element 1 using light emission driving circuit 12. Ohtomo further teaches generating internal reference light 22″ by passing that source light through amplitude filter 56 associated with reference reflection prism 55, thereby performing an additional intensity modulation corresponding to near and far measurement conditions. Maleki teaches causing the reflected light and reference light to coherently interfere at photodetector 120.
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, 3, 5, 7, 8, 9, 10, 16-19, 22 are rejected under 35 U.S.C. 103 as being unpatentable over Ohtomo et al. (US 20070263202 A1, “Ohtomo”) in view Maleki et al. (US 20190154835 A1, “Maleki”).
An optical distance measurement device comprising:
a light source (Claim 1; para 47, 57; Fig. 3, the distance measuring light 22 emitted by a light emitting element 1);
a first modulator (Fig. 3, pa 52, light emission driving circuit 12 controls driving light emission of the light emitting element 1) configured to generate distance measurement light acquired by performing first modulation on light from the light source ([para 57: light-emission driving circuit 12 causes light-emitting element 1 to emit and be modulated at a predetermined frequency, producing distance-measuring light 22.);
a light transmitter configured to transmit the distance measurement light to a measurement object (Ohtomo teaches the transmitting optical path, including optical fiber 61, deflection mirror 62, condenser lens 48, reflection mirror 45, and projection window 28. See at least Fig. 3, para 46- 47, 57- 58);
a light receiver (Fig. 3, Ohtomo teaches photodetection element 7 and its receiving optical path configured to receive reflected light being reflected from the measurement object by the transmitted distance measurement light (Claim 1, para 47, 51, 61);
a second modulator (Fig. 3, amplitude filter 56, reference reflection prism 55, and their relative movement produced by second rotating motor 52.) configured to generate reference light acquired by performing intensity modulation, which is second modulation, on the light from the light source according to a distance measurement range (Ohtomo’s amplitude filter 56, reference reflection prism 55, second rotating motor 52, and associated control collectively correspond to the claimed second modulator. The filter performs a second intensity modulation on light originating from light-emitting element 1, and the resulting intensity-modulated light is reflected and received as internal reference light 22″. The available reference-light levels are established to encompass near- and long-distance return-light conditions, and an appropriate reference level is selected according to the reflected measurement-light amount. See Claims 2-4, 6-7; para 42- 43, 45, 59, 62, 67, 69);
a detector configured to generate a reception signal by causing the received reflected light and the generated reference light (Para 61-62 and 64) (to interfere with each other); and
a distance calculator (Fig. 3, control computation unit 15) configured to calculate a distance to the measurement object, based on the transmitted distance measurement light and the generated reception signal (Para 64. See also, para 14, claims 1 and 6).
Ohtomo fails to explicitly teach but Maleki teaches that the detector configured to generate a reception signal by causing the received reflected light and the generated reference to interfere with each other (Para 121. See also, Claims 1, 5, 18).
It would have been obvious to one of ordinary skill in the art to modify Ohtomo’s distance measuring device to employ Maleki’s detector. Doing so will improve sensitivity and phase accuracy in optical distance measurement systems. Applying Maleki’s coherent detection to Ohtomo’s system would have predictably improved measurement robustness and accuracy, particularly for weak reflected signals.
Regarding claim 3, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 1, wherein the reference light has intensity in a specific distance measurement range, that is stronger than intensity in another distance measurement range (Ohtomo, Para 67, The amount of the light amount change of the internal reference light 22'' is set in such manner that it is equal to or more than the change of the light amount of the reflected distance measuring light 22' from the object to be measured at near distance and the light amount of the reflected distance measuring light 22' from the object to be measured at long distance. More concretely, the light amount change of the internal reference light 22'' should be set to the maximum value in the dynamic range of the photodetection unit or within the dynamic range. See also, para 68-69, reference signal is divided to levels … L1, L2, L3, L4, L5 and para 71, selects an internal reference standard to match the light amount).
Regarding claim 5, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 1, wherein intensity of the reference light changes to a pulse shape.
Maleki teaches that the reference light has a pulse shape, because Maleki explicitly discloses generating a “pulsed series of optical chirps” (Para 51-52, Fig. 8).
Maleki further teaches that each optical chirp generated by the laser serves as a local oscillator (LO) reference chirp when combined with reflected light at the photodetector (Para 120-121). Accordingly, the intensity of the reference light varies in time as a pulse shape corresponding to the pulsed optical chirps.
It would have been obvious to one of ordinary skill in the art to configure the reference light to have a pulse shape, as taught by Maleki, because using pulsed optical chirps in a coherent optical distance measurement system improves signal-to-noise ratio, reduces interference from out-of-range reflections, and enables controlled timing alignment between transmitted and reference signals. Applying such pulsed operation to the reference light generated from the same coherent light source as the transmitted signal represents a predictable use of a known technique to achieve improved measurement robustness and processing efficiency without changing the fundamental operation of the optical interference-based distance measurement system.
Regarding claim 7, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 5, wherein
the light transmitter repeatedly transmits the distance measurement light at a predetermined distance measurement period (Ohtomo teaches repeated projection of distance measuring light during rotary irradiation/scanning (Para 30 and 58) under a controlled measurement sequence (Para 53-54), and the second modulator generates the reference light for each of the distance measurement periods (Ohtomo further teaches that the second modulator generates reference light for each distance-measurement period. During each rotary scan, distance-measuring light 22 traverses amplitude filter 56 and reference reflection prism 55, whereby its light amount is changed and the resulting light is received as internal reference light 22″. Ohtomo states that the photodetection element receives one reflected distance-measuring light and one internal reference light as reflection mirror 45 is rotated by one turn. Accordingly, Ohtomo generates a corresponding intensity-modulated internal reference light during each recurring one-rotation distance-measurement period. See Ohtomo, paragraphs [0062], [0066]-[0067], and Figure 4A.).
Regarding claim 8, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 7, wherein the second modulator generates the reference light in the distance measurement range in which a distance from the optical distance measurement device is different, for each of the distance measurement periods (Ohtomo, "a Ref internal reference light corresponding to the light quantity of the reflected distance measurement light 22' is selected" so as to change the "light quantity variation of the internal reference light 22'" so as to "equal the change in the light quantity of the reflected distance measurement light 22' from a measurement object at a close distance and the light quantity of the reflected distance measurement light 22' from a measurement object at a long distance" (paragraphs 67 and 71),).
Regarding claim 9, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 8, wherein the second modulator generates the reference light in generation order in such a way that the distance measurement range becomes far from the optical distance measurement device or the distance measurement range becomes close to the optical distance measurement device (Ohtomo teaches generating internal reference light sequentially during a distance-measurement operation as the distance measuring light is projected by rotary irradiation or scanning (Para 66). Specifically, each time the distance measuring light traverses the reference reflection prism during scanning, the light is reflected and received as internal reference light (Para 62). Ohtomo further teaches configuring the internal reference light such that its light amount corresponds to distance measurement ranges including near distance and long distance targets, by setting the variation range of the internal reference light to cover changes in reflected signal strength for both near and far objects (Para 67). Accordingly, as the scanning operation proceeds, the internal reference light is generated in a temporal (generation) order corresponding to distance measurement ranges becoming closer to or farther from the optical distance measurement device, as recited in claim 9.).
Regarding claim 10, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 9, wherein the second modulator generates the reference light in such a way that the distance measurement ranges in reference light before and after in the generation order overlap with each other (As discussed in claim 9, Ohtomo teaches generating internal reference light sequentially during scanning as the distance measuring light traverses a reference reflection prism (Para 62, 66). Ohtomo further teaches that the internal reference light intensity is varied continuously by an amplitude filter whose density gradually changes as the distance measuring light traverses the reference reflection prism (Para 42 and 67). Because the internal reference light varies continuously and is generated sequentially in time, reference light generated immediately before and after in the generation order necessarily corresponds to overlapping distance measurement ranges rather than discrete, non-overlapping ranges. Therefore, Ohtomo teaches generating the reference light such that distance measurement ranges in reference light before and after in the generation order overlap with each other, as recited in claim 10.).
Regarding claim 16, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 1, wherein intensity of the reference light continuously changes according to the distance measurement range (Ohtomo, para 42 “density is continuously changed” and para 67 “light amount … is gradually changed”).
Regarding claim 17, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 16, wherein intensity of the reference light changes to a linear taper shape (Ohtomo, para 42, density is continuously changed … transmitting light amount is continuously decreased or continuously increased. A continuously changing density corresponds to a linear (or near-linear) taper).
Regarding claim 18, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 17, wherein intensity of the reference light changes in proportion to a distance from the optical distance measurement device (Ohtomo, para 62, 66, Reference prism traversed during distance-measuring scan (Reference light intensity varies as a function of traversal position during scanning) and para 67, …set to cover … near distance and … long distance (Intensity variation is explicitly set to cover near and far distances). Because scanning position corresponds to measurement distance, and reference intensity is varied continuously across traversal, intensity changes proportionally with distance.).
Regarding claim 19, Ohtomo, in view of Maleki, teaches the optical distance measurement device according to claim 16, wherein intensity of the reference light changes to a curved taper shape (Ohtomo, Para 42, density may be changed stepwise so far as density is substantially and gradually changed. A stepwise or non-uniform density profile corresponds to a curved (non-linear) taper).
Claim 22 is a method claim corresponding to system claim 1. It is rejected for the same reason.
Claims 2, 11-14 are rejected under 35 U.S.C. 103 as being unpatentable over Ohtomo in view Maleki and Sadao Yamashita (US 20020154051 A1).
Regarding claim 2, Ohtomo, in view of Maleki, fails to explicitly teach the optical distance measurement device according to claim 1, wherein the reference light has intensity in a case where the distance measurement range is far from the optical distance measurement device, that is stronger than intensity in a case where the distance measurement range is close to the optical distance measurement device. However, Yamashita teaches that received signal strength decreases rapidly with distance (1/R⁴) and that system amplitude/gain must be increased for far distances and reduced for near distances to prevent saturation and maintain sensitivity (Para 4-7, 11, 45).
It would have been obvious to one of ordinary skill in the art to configure the reference light in Ohtomo to be stronger for far distance measurement ranges than for close distance ranges, as taught by Yamashita, in order to compensate for reduced return strength at longer distances and avoid saturation at shorter distances.
Regarding claim 11, Ohtomo, in view of Maleki, fails to explicitly teach the optical distance measurement device according to claim 7, wherein intensity of the reference light is different for each of the distance measurement periods. However, Yamashita teaches that amplitude/gain is varied in accordance with distance, which in FMCW systems is determined per modulation cycle (per measurement period) via beat frequency (Para 11, 47-53, 60).
Regarding claim 12, Ohtomo, in view of Maleki, fails to explicitly teach the optical distance measurement device according to claim 7, wherein a width of the reference light varies according to the distance measurement range. However, Yamashita teaches varying signal processing bandwidth and weighting according to distance in order to optimize signal-to-noise ratio and avoid saturation (Para 11, 58-59),
It would have been obvious to one of ordinary skill in the art at the time of the invention to configure the reference light in Ohtomo in view of Yamashita such that its width varies according to the distance measurement range. Doing so, will optimize signal-to-noise ratio and avoid saturation.
Regarding claim 13, Ohtomo, in view of Maleki and Yamashita, teaches the optical distance measurement device according to claim 12, wherein the reference light has a width in a case where the distance measurement range is far from the optical distance measurement device, that is narrower than a width in a case where the distance measurement range is close to the optical distance measurement device (Yamashita, Para 7, 11, 59, teaches that far-distance signals require tighter signal conditioning than near-distance signals. Applying narrower reference-light widths for far distance ranges than for close distance ranges would have been an obvious design choice to improve detection reliability at long distances while avoiding saturation at short distances.).
Regarding claim 14, Ohtomo, in view of Maleki and Yamashita, teaches the optical distance measurement device according to claim 12, wherein the reference light has a width in a specific distance measurement range, that is narrower than a width in another distance measurement range (Yamashita, Para 7, 11, 59, teaches that far-distance signals require tighter signal conditioning than near-distance signals. Applying narrower reference-light widths for far distance ranges than for close distance ranges would have been an obvious design choice to improve detection reliability at long distances while avoiding saturation at short distances,).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Ohtomo in view Maleki and Garry N. Link (US 5850409 A, “Link”).
Regarding claim 4, Ohtomo, in view of Maleki, fails to explicitly teach but Link teaches the optical distance measurement device according to claim 1, wherein average power of the reference light is the same as power of the light from the light source before performing the intensity modulation (col 2: lines 7-8, col 3: lines 34-39; claim 7 “controlling the first current to provide a predetermined average optical signal from the laser”).
It would have been obvious to incorporate a known constant-average-power laser modulation technique into the Ohtomo, because maintaining constant average optical power during intensity modulation is a recognized requirement in coherent optical distance measurement systems to stabilize detector bias, preserve interference accuracy, and prevent measurement error. Such integration represents a routine design optimization yielding predictable improvements in stability and accuracy.
Claims 6, 15 are rejected under 35 U.S.C. 103 as being unpatentable over Ohtomo in view Maleki and Hartog (US 20130113629 A1, “Hartog”).
Regarding claim 6, Ohtomo, in view of Maleki, fails to explicitly teach the optical distance measurement device according to claim 5, wherein a width of the reference light is wider than a width of the distance measurement light.
However, Hartog teaches that the distance-measurement light is generated by modulating an optical signal to form a pulse that is launched into the sensing fiber, the pulse having a finite temporal duration (Para 44; see also example pulse duration in (Para 69). The reference further teaches that the reference (local oscillator) light used for coherent detection is continuous light coming directly from the optical source and is not pulsed (Para 43–44 and 82). Because the reference light is continuous while the distance-measurement light is a finite-duration pulse, the temporal width of the reference light is wider than the temporal width of the distance-measurement light, as recited in claim 6.
It would have been obvious to one of ordinary skill in the art at the time of the invention to apply the pulse-versus-continuous reference configuration taught by Hartog to the optical distance measurement device of Ohtomo in order to improve signal-to-noise ratio, stabilize interference detection, and enable reliable coherent mixing across the full measurement window, particularly where reflected measurement signals are temporally limited.
Regarding claim 15, Ohtomo, in view of Maleki, fails to explicitly teach the optical distance measurement device according to claim 7, wherein the second modulator generates a plurality of beams of the reference light for each of the distance measurement periods.
However, Hartog teaches an optical modulator configured to generate a plurality of reference (local oscillator) optical signals by producing multiple modulation sidebands from a light source, which are used concurrently during a single measurement cycle for coherent detection (Para 129-131, para 135-136, Fig. 25). It would have been obvious to one of ordinary skill in the art to modify Ohtomo’s reference-light generation to produce a plurality of reference light beams as taught by Hartog, since Ohtomo already relies on reference light for distance calculation and Hartog demonstrates that multiple reference beams improve signal robustness, noise tolerance, and measurement reliability during a measurement period. Such a modification represents a predictable use of known modulation techniques to improve the performance of Ohtomo’s distance measurement system.
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 extension fee 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 date of this final action.
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/JEMPSON NOEL/Examiner, Art Unit 3645
/YUQING XIAO/Supervisory Patent Examiner, Art Unit 3645
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