Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Detailed Action
Status of the Claims
1. This action is in response to the applicant’s filing on April 21, 2023. Claims 1-20 are
pending.
Claim Rejections – 35 USC § 102
2. 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.
3. Claims 1, 4-8, 10-11, & 13-20 are rejected under 35 U.S.C. 102 (a)(1) as being unpatentable over Li et al (US 20190310354 A1), hereinafter Li.
4. Regarding claims 1, 19 & 20:
Li teaches a method performed by a processor for dynamically calibrating a light detector of a light detection and ranging (LiDAR) system, ([0002]: The present disclosure relates to light detection and ranging (LiDAR), and in particular to LiDAR systems and methods for use in a vehicle). Li further teaches, ([0068]: It is to be understood that any or each module or state machine discussed herein may be provided as a software construct, firmware construct, one or more hardware components, or a combination thereof. For example, any one or more of the state machines or modules may be described in the general context of computer-executable instructions, such as program modules, that may be executed by one or more computers or other devices).
Li teaches obtaining an indication for use, ([0050]: The calibration sweep may be initiated on a time interval, at system startup, when unusual data is detected by the LiDAR control software, when a temperature sensor outside of the circuit detects temperature changes, during dead time of normal operation, or by other methods).
Li teaches determining, based on the indication, whether to perform the calibration of the light detector operating with a first bias voltage, ([0056]: FIG. 12 shows an illustrative process 1200 according to an embodiment. Process 1200 represents control circuit logic that may be used, for example, by circuit 1100. Starting at step 1210, a controller such as controller 1130 observes a signal amplitude generated by a LiDAR laser return pulse. The controller then compares the signal amplitude with a desired range of signal amplitudes as indicated by step 1220. In step 1230, a determination is made as to whether the signal amplitude is appropriate for linear data processing according to a pre-determined range of desired signal amplitudes. If the determination is YES, process 1200 maintains existing bias voltage as shown in step 1240. If the determination is NO, process 1200 then determines whether the signal amplitude is too low or too high, as shown in step 1250. If the determination is made that the signal amplitude is too HIGH, process 1200 then decreases bias voltage as shown in step 1260. If the determination is made that the signal amplitude is too LOW, process 1200 then increases bias voltage as shown in step 1270. Process 1200 then commands the system to run its next LiDAR system laser scan).
Li teaches in accordance with a determination to perform the calibration, initiating a multiple-point calibration of the light detector across a bias voltage scanning range, and determining, based on the multiple-point calibration, whether to update the first bias voltage based on the second bias voltage, ([0007]: In another embodiment, a method for using a LiDAR system is provided that includes an avalanche photo diode (APD), a variable voltage source, and an amplifier, is provided. The method can include conducting a bias voltage calibration that instructs the variable voltage source to sweep through a plurality of applied bias voltages; monitor an output of the amplifier during the bias voltage calibration sweep; determining an avalanche threshold voltage of the APD based on the monitored output; and setting the applied bias voltage, via the variable voltage source, to an optimal applied bias voltage based on the determined avalanche voltage, wherein the optimal applied bias voltage is less than the determined avalanche voltage).
Li teaches the multiple-point calibration comprises determining a second bias voltage corresponding to a current temperature in an operating environment of the light detector, ([0006]: In one embodiment, a method for using a LiDAR system that includes an avalanche photo diode (APD), a variable voltage source, and a temperature sensor, is provided. The method can include receiving a temperature value from the temperature sensor, determining a bias voltage to be applied to the APD based on the received temperature such that the applied bias voltage does not exceed an avalanche voltage threshold of the APD, and controlling the variable voltage source to apply the determined bias voltage to the APD). Li further teaches, ([0050]: The calibration sweep may be initiated on a time interval, at system startup, when unusual data is detected by the LiDAR control software, when a temperature sensor outside of the circuit detects temperature changes, during dead time of normal operation, or by other methods).
5. Regarding claims 19 & 20:
Li teaches a LiDAR system and a vehicle, ([0002]: The present disclosure relates to light detection and ranging (LiDAR), and in particular to LiDAR systems and methods for use in a vehicle).
6. Regarding Claim 4:
Li teaches determining whether to update the first bias voltage comprises:
calculating a fitting quality parameter based on the linear fitting; and determining to update the first bias voltage based on the second bias voltage when the fitting quality parameter satisfies a predetermined threshold, ([0045]: FIG. 5A shows an illustrative plot of signal intensity as a function of bias voltage according to an embodiment. Signal intensity refers to the output of the avalanche photo diode. Using appropriate physical models, the breakdown voltage of the APD device, V.sub.BR, can be obtained through curve fitting, even though the signal is strongly saturated when the bias voltage reaches VBR. FIG. 5B shows an illustrative plot of the relationship between the physical breakdown voltage and the avalanche voltage threshold at different temperatures for certain APD devices. It is clear that for some APD devices, a simple linear formula can be used to predict the avalanche voltage threshold based on the measured breakdown voltage. For other APD devices, the relationship between the physical breakdown voltage and the avalanche voltage threshold may not be as simple, but in general the avalanche voltage threshold can still be characterized as a function of breakdown voltage and temperature. Combining FIG. 5A and FIG. 5B, it is therefore possible to obtain the APD breakdown voltage at any temperature through a bias voltage scan, and then use a pre-defined formula to predict the corresponding avalanche voltage threshold at that temperature).
7. Regarding Claim 5:
Li teaches updating the first bias voltage based on the second bias voltage, [0047] FIG. 7 shows an illustrative process 700 according to an embodiment. Process 700 may represent the control circuit logic that may be used, for example, by circuit 600. Starting at step 710, a temperature sensor such as temperature sensor 630 records avalanche photo diode temperature. A controller (e.g., controller 640) receives the avalanche photo diode temperature as indicated by step 720. The controller then determines a desired bias voltage based, as least in part, on the temperature it receives, as indicated by step 730. In step 740, a determination is made as to whether the existing bias voltage matches a desired voltage for the measured temperature. If the determination is NO, process 700 can adjust bias voltage by setting the existing bias voltage equal to the desired voltage as indicated by step 750. If the determination is YES, process 700 can maintain the existing bias voltage as indicated by step 760.
8. Regarding Claim 6:
Li teaches wherein the light detector comprises an avalanche photodetector (APD), See Claim 1
Li teaches wherein the bias voltage scanning range is based on a breakdown voltage of the APD, ([0052]: FIG. 9 shows an illustrative process 900 according to an embodiment. Process 900 may represent the control circuit logic that may be used, for example, by circuit 800. Starting at step 910, a controller such as controller 830 initiates a bias voltage calibration sweep. The controller commands a voltage generator such as voltage generator 810 to sweep bias voltages across a predefined range of bias voltages as indicated by process 920. The controller then records amplifier output data produced by the bias voltage sweep according to step 930. In step 940, the controller detects photo diode avalanche voltage threshold or the breakdown voltage threshold based on recorded amplifier output data across the bias voltage sweep voltage range. In step 950, the controller sets the bias voltage to an ideal bias voltage based on the detected avalanche voltage. In one embodiment, the controller may determine the ideal bias voltage by applying the detected avalanche voltage or breakdown voltage to a formula. For example, the formula can subtract a fixed value from the detected avalanche voltage or the breakdown voltage threshold to yield the ideal bias voltage). Li further teaches, ([0055]: FIG. 11 shows an illustrative bias voltage modulation control circuit diagram, according to an embodiment. Circuit 1100 may contain voltage generator 1110, photo diode 1120, controller 1130, and amplifier 1140. Return pulses interact with photo diode 1120, which produces an output in response thereto and that output is amplified by amplifier 1140. To ensure that diode 1120 produces data that is suitable for data analysis, control circuitry 1130 ensures the bias voltage remains below the avalanche voltage threshold (as discussed above) and may also modulate the bias voltage as part of a modulation feedback loop that is designed to compress relatively high gain signals and boost relatively low gain signals. Control circuitry 1130 may modulate the bias voltage to ensure that the signal gain provided by diode 1120 is within an amplitude range suitable for data processing. Control circuitry 1130 may modulate the bias voltage based on a previously received output (e.g., signal gain) of diode 1120 (which output is received via amplifier 1140). For example, if the signal gain is too high, controller 1130 may reduce the bias voltage. If the signal gain is too low, controller 1130 may increase the bias voltage. Controller 1130 may ensure that diode 1120 operate below its avalanche voltage threshold such that bias voltages can be modulated up or down to produce desired signal gains without exceeding the avalanche voltage threshold).
9. Regarding Claim 7:
Li teaches the multiple-point calibration further comprises selecting the bias voltage scanning range based on a maximum bias voltage of the light detector, See Claim 6.
10. Regarding Claim 8:
Li teaches the multiple-point calibration further comprises selecting a lower limit of the bias voltage scanning range based on a current intensity ratio of the light detector, ([0045]: FIG. 5A shows an illustrative plot of signal intensity as a function of bias voltage according to an embodiment. Signal intensity refers to the output of the avalanche photo diode. Using appropriate physical models, the breakdown voltage of the APD device, VBR, can be obtained through curve fitting, even though the signal is strongly saturated when the bias voltage reaches VBR. FIG. 5B shows an illustrative plot of the relationship between the physical breakdown voltage and the avalanche voltage threshold at different temperatures for certain APD devices. It is clear that for some APD devices, a simple linear formula can be used to predict the avalanche voltage threshold based on the measured breakdown voltage. For other APD devices, the relationship between the physical breakdown voltage and the avalanche voltage threshold may not be as simple, but in general the avalanche voltage threshold can still be characterized as a function of breakdown voltage and temperature. Combining FIG. 5A and FIG. 5B, it is therefore possible to obtain the APD breakdown voltage at any temperature through a bias voltage scan, and then use a pre-defined formula to predict the corresponding avalanche voltage threshold at that temperature). Li further teaches, ([0064]: At step 1540, an initial bias voltage can be determined based on the anticipated avalanche voltage threshold and a voltage offset. The voltage offset can set the initial bias voltage to a voltage level that is lower than the anticipated avalanche voltage threshold. The initial bias voltage can be determined using equation 1 above. At step 1550, an active scanning event bias voltage can be determined based on the initial bias voltage and a temperature received by the temperature sensor, wherein the active scanning event bias voltage is applied to the avalanche photodiode by the variable voltage source to prevent the avalanche photodiode from operating at or above the anticipated avalanche voltage). Li continues to teach, ([0060]: “V_Bias0 can represent the bias voltage at the start of LiDAR scanning event. For certain APD devices, V_Bias0 can be calculated approximately using a simplified equation (1) below”. “V_BR0 is the avalanche photodiode breakdown voltage based on an initial system calibration, S and E are fit constants representing a linear relationship between the breakdown voltage and the avalanche voltage threshold, and V_Offset is the operating voltage offset from the avalanche voltage threshold. The product of V_BR0 and S produces the anticipated avalanche threshold”. Li goes on to teach, ([0059]: The value chosen for V_Offset 1414 can be selected based on how aggressive or conservative system 1400 desires to run the avalanche photodiode. A larger V_offset corresponds to a conservative approach whereas a smaller V_Offset corresponds to an aggressive approach. The closer V_Bias operates to the breakdown voltage, the better the intensity response is from the avalanche photodiode). Li continues to teach, ([Equation 1]: V_Bias0 = V_BRO*S + E – V_Offset).
Rearranging Equation 1, dividing both sides by V_BRO*S, yields:
(V_Bias0 / V_BRO*S) = 1 + ((E – V_Offset )/ V_BRO*S)
Thus, V_BRO*S is determined based on the intensity response of the detector at varying temperatures and the initial bias voltage (V_Bias0) or lower limit of the bias voltage scan can be selected base on the ratio of the initial bias voltage and the anticipated avalanche threshold at a given temperature.
11. Regarding Claim 10:
Li teaches the indication is obtained based on one or more criteria. See Claim 1
12. Regarding Claim 11:
Li teaches one or more criteria is based on a change in temperature in the operating environment of the light detector. See Claim 1
13. Regarding Claim 13:
Li teaches one or more criteria is based on a vehicle condition. See Claim 1
14. Regarding Claim 14:
Li teaches the vehicle condition comprises one or more of the following: a LiDAR usage status, and a LiDAR usage condition. See Claim 1
15. Regarding Claim 15:
Li teaches one or more criteria is based on a calibration policy, ([0051]: In some embodiments, circuit 800 may be used to determine the breakdown voltage of diode 820. The breakdown voltage may be determined as part of a LiDAR system initiation, at the start of LiDAR scanning event, or any other suitable trigger event. In some embodiments. the determination of the breakdown voltage may be used as an input in a calculation equation for determining the initial Vbias (as discussed down below in connection with FIG. 14)).
16. Regarding Claim 16:
Li teaches the calibration policy comprises one or more priority rules pertaining to the one or more criteria, ([0056]: FIG. 12 shows an illustrative process 1200 according to an embodiment. Process 1200 represents control circuit logic that may be used, for example, by circuit 1100. Starting at step 1210, a controller such as controller 1130 observes a signal amplitude generated by a LiDAR laser return pulse. The controller then compares the signal amplitude with a desired range of signal amplitudes as indicated by step 1220. In step 1230, a determination is made as to whether the signal amplitude is appropriate for linear data processing according to a pre-determined range of desired signal amplitudes. If the determination is YES, process 1200 maintains existing bias voltage as shown in step 1240. If the determination is NO, process 1200 then determines whether the signal amplitude is too low or too high, as shown in step 1250. If the determination is made that the signal amplitude is too HIGH, process 1200 then decreases bias voltage as shown in step 1260. If the determination is made that the signal amplitude is too LOW, process 1200 then increases bias voltage as shown in step 1270. Process 1200 then commands the system to run its next LiDAR system laser scan). Li further teaches, ([0050]: The calibration sweep may be initiated on a time interval, at system startup, when unusual data is detected by the LiDAR control software, when a temperature sensor outside of the circuit detects temperature changes, during dead time of normal operation, or by other methods).
17. Regarding Claim 17:
Li teaches obtaining the indication comprises obtaining the indication from a vehicle control module, ([0012]: FIG. 1 shows an illustrative vehicle having a LiDAR system that is attached to and/or incorporated therein, according to an embodiment). Li further teaches, ([0050]: The calibration sweep may be initiated on a time interval, at system startup, when unusual data is detected by the LiDAR control software, when a temperature sensor outside of the circuit detects temperature changes, during dead time of normal operation, or by other methods). Since the temperature sensor is outside of the circuit it must be connected to a controller outside of the LiDAR system. This would indicate the temperature sensor is connected to a control module within the vehicle, not directly connected to the LiDAR subsystem. Thus, the indication to begin a calibration sweep comes from a vehicle control module. In addition, the calibration at system startup would be initiated upon starting the vehicle. In this case a vehicle control module would send a signal to the LiDAR controller to power up, beginning the startup procedure, including the calibration sweep. Thus, the indication is the startup itself, coming from a vehicle controller.
18. Regarding Claim 18:
Li teaches wherein obtaining the indication comprises obtaining the indication at regular intervals. See Claim 1
Claim Rejections – 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness
rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not
identically disclosed as set forth in section 102, if the differences between the claimed invention and
the prior art are such that the claimed invention as a whole would have been obvious before the
effective filing date of the claimed invention to a person having ordinary skill in the art to which the
claimed invention pertains. Patentability shall not be negated by the manner in which the invention was
made.
19. Claims 9 & 12 are rejected under 35 U.S.C. 103 as being unpatentable over Li et al (US 20190310354 A1), hereinafter Li, in view of Anderson et al (US 5929982 A), hereinafter Anderson.
20. Regarding Claim 9:
Li does not teach the bias voltage scanning range is between 95% to 100% of a maximum bias voltage of the light detector.
However, Anderson teaches, ([Abstract]: An active avalanche photo-diode, APD, gain control circuit for use in an optical receiver includes a bias generator for varying the bias on a variable gain APD in response to bias control values generated by a controller). Anderson further teaches, ([Col. 2, Lines 39-41]: InGaAs APD, manufactured and sold by NEC, Corp., is 0.2%/.degree.C. with a typical breakdown voltage of 70 volts). Anderson continues to teach, ([Col. 2, Lines 56-61]: the APD bias must be set at about 2.5 volts below breakdown to guarantee the APD will not go into breakdown. Preventing the APD from going into breakdown is a significant requirement in OTDR instrument design because of the possibilities of instrument damage and complete instrument failure if the APD goes into breakdown). Thus, the target bias voltage has an upper limit of 67.5 volts. Anderson goes on to teach, ([Col. 4, Lines 16--21]: The bias control values are generated from an initial bias control value producing a bias voltage on the avalanche photo-diode in the range of about five volts below the breakdown voltage with the bias control values being incremented to produce changes in the bias voltage in the range of about 0.1 volts). Thus a bias voltage calibration scan comprising a range from 65 – 67.5 volts, indicating a calibration sweep range of 96% to 100% of maximum bias voltage.
It would have been obvious to one of ordinary skill in the art at the time of filling to modify Li with Anderson to include a calibration sweep range of 95% - 100% since the courts have held, in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05 I. One of ordinary skill in the art at the time of filing would have been motivated to modify Li with Anderson since, (Anderson: [Col. 2, Lines 57-61]: Preventing the APD from going into breakdown is a significant requirement in OTDR instrument design because of the possibilities of instrument damage and complete instrument failure if the APD goes into breakdown).
21. Regarding Claim 12:
Li does not teach determining whether to perform the calibration comprises
determining whether the change in temperature satisfies a predetermined threshold.
However, Anderson teaches , ([Abstract]: An active avalanche photo-diode, APD, gain control circuit for use in an optical receiver includes a bias generator for varying the bias on a variable gain APD in response to bias control values generated by a controller). Anderson further teaches, ([Col. 5, Lines 61-67, & Col. 6, Lines 1-2]: Additional steps for increasing the dynamic range of the optical time domain reflectometer include measuring a temperature representative of the temperature of the avalanche photo-diode, comparing the measured temperature to a threshold value, and initiating the generation of additional bias control values for reestablishing the optimum bias for the optimum gain of the avalanche photo-diode when the change in temperature exceeds the temperature threshold).
It would have been obvious to one of ordinary skill in the art at the time of filling to modify Li with Anderson to include a temperature change threshold for calibration since, it is the same field of endeavor and results would have been predictable. One of ordinary skill in the art at the time of filing would have been motivated to modify Li with Anderson since, (Anderson: [Col. 2, Lines 57-61]: Preventing the APD from going into breakdown is a significant requirement in OTDR instrument design because of the possibilities of instrument damage and complete instrument failure if the APD goes into breakdown).
Allowable subject matter
22. Claims 2 & 3 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. In addition, applicant should be aware that Anderson teaches all limitations for Claim 3 when considered without the limitations of Claim 2.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's
disclosure.
US 9575184 B2: Discloses a LiDAR sysem with APD array, bias voltage circuit, and ROIC.
US 20180284245 A1: Discloses a LiDAR system and method for dynamic calibration of bias voltage.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAMES W NAPIER whose telephone number is (571)272-7451. The examiner can normally be reached Monday - Friday 8:00 am - 4:00 pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Helal Algahaim can be reached at (571) 272-5227. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/J.W.N./Examiner, Art Unit 3645
/HELAL A ALGAHAIM/SPE , Art Unit 3645