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 1-12, 17-42 are currently pending and examined below.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 07/13/2026 has been entered.
Response to amendment
This is a non-final Office action in response to applicant's remarks/arguments filed on 07/13/2026.
Status of the claims:
Claims 1, 27, 42 have been amended.
Applicant’s arguments, see Remarks pages 9-13, filed 07/13/2026, with respect to the rejections of claims 1-12, 17-42 under 103 have been fully considered and are not persuasive. Therefore, the rejection is maintained.
Applicant argues that PHY1076-01’s bias-loop settling time is not the claimed “predetermined delay time” because the settling time merely permits the control loop to stabilize, whereas the claimed delay defines a diagnostic observation time at which the drive-signal state is captured and evaluated. Applicant further argues that neither Milgrome nor PHY1076-01 teaches capturing the state of the drive signal during energization of the addressed laser and comparing that captured state with a desired state corresponding to the control signal.
Applicant’s arguments are not persuasive. The claims do not require that the predetermined delay be arbitrarily selected, do not exclude a delay provided to permit stabilization, and do not require that the drive signal be monitored throughout the delay period. PHY1076-01 teaches that, after the laser is turned on, the bias-control loop is allowed to settle for predetermined settling time tsettle before the safety-control loop is enabled. Thus, the safety determination is intentionally performed only after expiration of a predetermined interval following activation of the laser-control operation. PHY1076-01 further identifies predetermined settling times of 5 ms and 500 µs depending on the selected loop-bandwidth setting. The fact that the delay also avoids evaluation during transient settling does not distinguish it from the broadly recited predetermined delay.
Corresponding passages:
PHY1076-01, Section 4.4.1, “PHY1076-01 Fault Management,” pages 19–20: “When the Laser is turned on, during power up or after a fault, there will be a short period during which the bias control loop is allowed to settle (tsettle) before the safety control loop circuit is enabled.”
PHY1076-01, Section 3.4.3, “Laser Mean Power Control Loop,” page 7: bias-loop settling time tsettle is 5 ms for Loop_BW = 0 and 500 µs for Loop_BW = 1.
PHY1076-01, Section 4.3.1, pages 17–18: Loop_BW controls the response of the control loop and is selected to provide stability and the required transmitter startup time.
Applicants’ arguments regarding the amendments are not persuasive. Milgrome teaches that laser-control signals 418–420 energize respective laser diodes by controlling corresponding switches SDL1–SDLn. During laser operation, local energy monitor 414 monitors, i.e., captures, the voltage at internal node 404. Node 404 is directly coupled to the laser diodes, and its voltage, together with the conduction resistance and duration of the corresponding switch, determines the drive current and optical power of the energized laser. Milgrome’s comparator U1 compares the captured node-404 voltage with threshold voltage 422 supplied by control device 450.
Corresponding passages:
Milgrome, paragraph [0074] and Figure 4: comparator U1 compares the filtered voltage of internal node 404 with threshold voltage 422 supplied by control device 450 and outputs safety-alarm signal 408.
Milgrome, paragraph [0075]: enable signals 418–420 control the duration and resistance with which switches SDL1–SDLn conduct current; the voltage across the laser terminals is the voltage at node 404; and laser-pulse power is controlled by the magnitude of current determined by the switch resistance and anode voltage.
Milgrome, paragraph [0077]: internal node 404 provides direct connectivity among energy rate limiter 410, electro-optical modulator 412, local energy monitor 414, capacitors C1-Cn, and laser diodes DL1–DLn.
Milgrome, paragraphs [0091] and [0093] and Figure 5B: the controller enables a selected discharge switch so current passes through the corresponding laser diode, while local energy monitor 414 monitors the voltage at node 404 during the operations of blocks 511-519.
Milgrome, Figure 5B: during the enabling and firing operations, the system monitors the capacitor voltage, compares it with a threshold, and asserts an alarm when the safety condition is violated.
PHY1076-01 teaches the additional feature that the desired comparison reference corresponds to a programmed laser-control value. Specifically, the actual monitor-photodiode current is compared with a reference current controlled by tx_power_set. Thus, tx_power_set establishes the desired commanded laser-operating state, while the monitor-photodiode current represents captured actual laser-operation feedback. PHY1076-01 also separately samples the actual laser-bias current using the Tx Bias ADC.
Corresponding passages:
PHY1076-01, Section 4.3, page 17: the laser driver operates with an analog mean-power control loop digitally programmed using the Mean Power DAC; mean laser power is measured using the MPD-current Tx Power ADC; and the Tx Bias ADC samples the laser-bias current.
PHY1076-01, Section 4.3.1 and Figure 15, page 17: “The Laser bias current is controlled by the mean-power control loop in which the current from the monitor photodiode in the TOSA is compared with a reference current controlled by tx_power_set.”
PHY1076-01, Table 3, page 17: tx_power_set is the eight-bit Mean Power DAC control having a rated range of 0–3 mA, while modulationDACDefault controls the laser modulation DAC.
PHY1076-01, Section 4.3.2, page 18: the modulation current may be directly controlled by writing a desired value to modulationDACDefault or through the programmed temperature-indexed lookup table.
The rejection does not rely on either reference alone but relies on modifying Milgrome’s drive-state monitoring and threshold comparison, as taught by PHY1076-01, so that the reference used in the comparison represents the desired state established by the generated control signal. It would have been obvious to one of ordinary skill in the art to make this modification because comparing the actual electrical drive condition with the commanded drive condition would detect an improperly driven, stuck-on, stuck-off, shorted, or open laser while PHY1076-01’s predetermined settling delay would avoid false fault indications caused by startup transients.
Corresponding passages supporting the modification and benefit:
Milgrome, paragraph [0075]: recognizes that one of the discharge switches SDL1–SDLn or laser-control signals 418–420 may fail and provides a safety mechanism to limit optical energy in the event of that single-component failure.
Milgrome, paragraph [0096]: describes simulating a fault in which a laser remains enabled irrespective of the alarm signal by maintaining the discharge switch connected or maintaining the laser-control signal in the enabled state.
PHY1076-01, Section 4.4, page 19: the laser-safety circuitry monitors potential faults, including faults involving the APC loop or bias current, and turns off the transmitter bias and modulation currents when a fault is detected.
PHY1076-01, Section 4.4.1, pages 19–20: the safety circuit shuts down and isolates the laser upon sensing a bias-current, supply-voltage, or reference-voltage fault and delays safety-loop activation until the bias-control loop has settled.
PHY1076-01, Section 4.4.1: an APC-loop fault causes TX_FAULT to latch and the laser to be disabled until the disable signal is pulsed to clear the condition.
Accordingly, Applicant’s arguments do not overcome the rejection of independent claims 1, 27, and 42, and the rejection is maintained.
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 42 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 42,” the drive signal” in line 7 lacks antecedent basis.
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 1-12, 17-18, 20-22, 26-33, 35-37, 41-42 are rejected under 35 U.S.C. 103 as being unpatentable over Milgrome et al. (US 20210041567 A1) in view of PHY1076-01” Maxim Integrated, 125Mbps to 2.7Gbps Laser Driver/ Post Amp with Digital Diagnostics, 2012”.
Regarding claim 1, Milgrome teaches a method for detecting a fault condition in a light detection and ranging (LiDAR) transmitter (Para 54), the method comprising:
a) generating a control signal that comprises an address and desired drive voltage and current information for a laser in a laser array (para 82-85, Fig. 3. Control device 350 sets the power for the laser array and addresses each laser to be in an "on" or "off" state. Para 76 discloses multiple channels. Each channel has its own modulator and is, therefore, independent. Furthermore, each channel has own laser diode. Therefore, each diode is addressable. See also, para 62, Milgrome teaches multiple laser control signals 318- 320, each corresponding to a respective laser diode. Each control signal selectively enables current through its corresponding diode and causes the corresponding laser signal to be transmitted.);
b) generating a drive signal for the laser in the laser array in response to the generated control signal and applying the generated drive signal to a contact associated with the address for the laser in the laser array, thereby energizing the laser at a desired output power for a desired time (Figs. 3 and 5B (Block 515); Milgrome teaches that each laser-control signal enables current to pass through the corresponding laser diode. Milgrome further explains that the current through each laser is controlled by the corresponding control signal and by the voltage at the laser terminal or anode. See Milgrome para 62, 65- 66. Milgrome also claims laser-control switches having control terminals, where the amount of current conducted through the respective laser depends on one or more properties of the laser-control signal. See Milgrome claims 23- 24.);
c) determining, (at a predetermined delay time after the generating of the control signal,) if the drive signal has a parameter with a value that is outside a threshold range for eye safety (Fig. 5B, monitor the voltage….) by capturing a state of the drive signal during energization of the laser (Milgrome teaches that laser-control signals 418-420 are placed in an enable state to connect corresponding discharge switches SDL1-SDLn, thereby permitting current to pass through and energize corresponding laser diodes DL1-DLn. During those operations, local energy monitor 414 monitors, i.e., captures, the voltage at internal node 404. See Fig. 5B and paragraphs para 91- 93. Internal node 404 is directly connected to the laser diodes, and the voltage at node 404, together with the conduction resistance and duration of the corresponding switch, determines the current through and optical power of the energized laser. Thus, the monitored node-404 voltage represents a captured state of the actual electrical drive signal during laser energization. See Fig. 4 and para 74-77. Milgrome further teaches comparator U1 comparing the captured voltage at node 404 with threshold voltage 422 supplied by control device 450 and generating safety-alarm signal 408 as the comparison result. The comparison result indicates whether the laser is operating in an acceptable or faulted health condition. See Fig. 4 and para 74- 75).
Milgrome fails to explicitly teach
c) determining, at a predetermined delay time after the generating of the control signal, if the drive signal has a parameter with a value that is outside a threshold range for eye safety by comparing the captured state to a desired state corresponding to the control signal;
d) storing, at the predetermined delay time after the generating of the control signal, the address and a fault condition if the parameter has the value outside the threshold range for eye safety;
e) reporting the address and the fault condition to a host that takes an action on the LiDAR transmitter in response to the fault condition.
As described above, Milgrome teaches capturing an actual electrical state associated with the drive of an energized laser diode and comparing that captured state with a reference threshold supplied by control device 450. Milgrome fails to explicitly teach that the comparison reference is a desired state corresponding to the generated control signal and further fails to explicitly teach performing the comparison after the recited predetermined delay.
PHY1076-01 teaches a laser driver having an analog mean-power control loop digitally programmed through the Mean Power DAC. Actual mean laser power is captured through the monitor-photodiode current, and actual laser-bias current is sampled using the Tx Bias ADC. See Section 4.3, Table 3, and Fig. 15, page 17.
PHY1076-01 further teaches that the actual monitor-photodiode current is compared with a reference current controlled by the programmed tx_power_set value. Thus, the actual feedback represents the captured state of the energized laser, while the reference controlled by tx_power_set represents the desired state corresponding to the programmed control value. See Section 4.3.1 and Fig. 15, page 17.
PHY1076-01 also teaches that, after the laser is turned on, the bias-control loop is allowed to settle for predetermined time tsettle before the safety-control loop is enabled. Therefore, the health or fault determination is performed after expiration of a predetermined delay following activation of the laser-control operation. See Section 4.4.1, pages 19-20; see also Section 3.4.3, page 7, identifying settling times of 5 ms and 500 µs.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Milgrome, as taught by PHY1076-01, so that the actual state of the laser drive signal captured during energization is compared with a desired reference state established by the generated control signal after expiration of a predetermined settling interval. PHY1076-01 teaches comparing actual laser operation feedback with a reference controlled by the programmed laser control value and delaying the safety comparison until the control loop has settled. The modification would have predictably enabled Milgrome’s safety system to determine whether the actual laser drive condition corresponds to the commanded drive condition, while avoiding false fault determinations caused by transient ramp-up or settling conditions. A person of ordinary skill would have recognized that PHY1076-01’s command dependent reference technique could likewise be applied to Milgrome’s electrical monitoring comparator by deriving the reference voltage or current from the commanded drive-voltage/current information, thereby permitting direct comparison of Milgrome’s captured electrical drive state with the expected electrical state for the selected laser.
Milgrome in para 63 teaches the safety alarm signal 308 may remain asserted until any suitable safety criteria are met (e.g., until a reset signal is received, until the voltage of internal node satisfies the safety condition, etc.). It would have been obvious to one of ordinary skill in the art to implement the retained safety-alarm condition using a latch, register, or other memory element so that the detected error condition remains available to controller 350 until the prescribed reset or recovery condition occurs. Such storage would permit the controller to prevent further laser operation and maintain the transmitter in a safe state after the transient condition that initially produced the fault may no longer be present. It would further have been obvious to store the known address of the laser being energized together with the retained fault condition because associating the fault with the affected laser would permit the controller or host to identify the failed channel and take laser specific corrective action.
Milgrome teaches a method for detecting a fault condition in a LiDAR transmitter, including generating a control signal comprising an address and desired drive voltage/current information for a laser in a laser array, generating and applying a corresponding drive signal to energize the addressed laser, monitoring a drive or bias parameter relative to an eye-safety threshold, and asserting and maintaining a fault or alarm condition associated with the addressed laser when the threshold is violated.
While Milgrome does not explicitly describe delaying the timing of the fault determination and storage relative to generation of the control signal, the PHY1076-01 laser driver explicitly teaches a predetermined delay following a laser enable or turn-on event before safety monitoring is performed. Specifically, PHY1076-01 states that “when the laser is turned on, during power up or after a fault, there will be a short period during which the bias control loop is allowed to settle (t_settle) before the safety control loop circuit is enabled” (see Section 4.4.1, “Fault Management,” pages 19-20; see also Section 3.4.3, “Bias Loop Settling Time (t_settle),” page 7). Thus, determination of whether a monitored drive or bias parameter is outside an eye-safety threshold is performed only after expiration of the predetermined settling time, rather than in real time. PHY1076-01 further teaches that operation outside fixed eye-safety limits causes a safety fault to be asserted (see Section 3.4.4, “Eye Safety Internal Fixed Limits,” page 8) and that detected safety faults are latched and maintained until reset (see Section 4.4.1, “Fault Management,” page 19), which constitutes storing the fault condition. It would have been obvious to one of ordinary skill in the art to incorporate this known delayed-enable safety monitoring and fault-latching technique into Milgrome’s addressed LiDAR fault-detection method so that the determination of whether the drive signal parameter is outside the eye-safety threshold and the storing of the address and fault condition are performed at the predetermined delay time after generating the control signal, as recited in claim 1, in order to avoid false fault indications during transient ramp-up conditions.
Milgrome teaches that each laser control signal 318- 320 corresponds to and selectively energizes a respective laser diode. Therefore, when the controller asserts a particular laser control signal, the controller knows the identity or address of the laser being operated. Milgrome further teaches that local energy monitor 306 measures node voltage and generates safety alarm signal 308 when the measured voltage violates the safety threshold. See Fig. 3 and para 62- 63.
Milgrome also teaches that the safety alarm signal is provided to control circuitry and may be used by control device 350, which is a programmable processing device or digital logic circuit external to the TOSA, to de-assert the energy control signal or the laser control signals when safe operating conditions are not met. Thus, Milgrome teaches communicating the detected fault condition to an external controller that takes protective action on the transmitter by disabling further energy transfer or laser operation. See Fig. 3 and para 64. Milgrome additionally teaches that the external controller supplies the respective laser-enable signals controlling the individual laser channels. See Fig. 4 and para 70- 72.
PHY1076-01 teaches the claimed host-reporting operation. Section 4.4.2, “MCU and Host Fault Management,” page 20, teaches that the MCU maintains and reports alarms and warnings, reports a detected fault through the TX_FAULT pin and STAT_CON register, and that the MCU or host may respond to the reported fault by asserting Soft Tx Disable to disable the laser.
Milgrome in view of PHY1076-01 does not explicitly teach that a laser address is included in the fault report. However, Milgrome individually operates the laser diodes using respective laser-control signals, such that the controller already knows the identity of the laser being energized when the fault is detected.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to report the detected fault condition to a host and permit the host to take protective action by disabling laser operation. It would further have been obvious to include the known address or identifier of the laser being energized with the reported fault condition because Milgrome individually controls respective laser diodes using corresponding laser control signals, and reporting the affected laser identifier would permit the host to identify the particular faulty laser channel and take targeted corrective, diagnostic, servicing, or operating action.
Regarding claim 2, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the laser comprises a group of lasers in the laser array (Para 71, claim 1 and figs. 3-4).
Regarding claim 3, Milgrome in view of PHY1076-01 teaches the method of claim 1 wherein the parameter comprises drive signal pulse duration (Para 66, optical pulse duration).
Regarding claim 4, Milgrome in view of PHY1076-01 teaches the method of claim 1 wherein the parameter comprises drive signal power (Para 63, 86).
Regarding claim 5, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the parameter comprises drive signal repetition rate (Para 66).
Regarding claim 6, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the drive signal comprises a low-side drive signal (Fig. 4, para 71-72, cathode terminal; each of one or more laser diodes (DLl-DLn) may receive an electric current from a power supply to its anode terminal when an electrical switch (SC l) is closed, and be energized when a laser enable signal is provided to an electrical switch connected to its cathode terminal).
Regarding claim 7, Milgrome in view of PHY1076-01 teaches the method of claim 1 wherein the drive signal comprises a high-side drive signal (Fig. 4, para 71-72, anode terminal; each of one or more laser diodes (DLl-DLn) may receive an electric current from a power supply to its anode terminal when an electrical switch (SC l) is closed, and be energized when a laser enable signal is provided to an electrical switch connected to its cathode terminal).
Regarding claim 8, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for eye safety comprises performing an XOR operation (Figs. 3-5, para 63, 86, a local energy monitor (306) may determine that a safety condition is violated when monitored voltage across a local energy storage (305) exceeds or is below a safety threshold voltage).
Regarding claim 9, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for eye safety comprises comparing the drive current to a predetermined low current value
Milgrome teaches that each laser-control switch controls the amount of current conducted through its respective laser based on properties of the corresponding laser-control signal, and that the optical-pulse power is controlled by the magnitude of current conducted through the laser diode. Milgrome also recognizes that a discharge switch or laser-control signal may fail. See Fig. 4, para 75, and claims 23–24. PHY1076-01 teaches that the Tx Bias ADC samples the actual laser-bias current, specifies a normal bias-current range beginning at 0.5 mA and an off-state current of 10 µA, and uses safety circuitry to detect faults involving the APC loop or bias current and assert TX_FAULT. See Sections 3.4.3, 4.3, and 4.4, pages 7, 17, and 19.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to sample the laser-drive current and compare the sampled current with a predetermined low-current value, because Milgrome recognizes that laser-control switches and control signals may fail and that laser output depends on the current conducted through the laser. Comparing the sampled drive current with a predetermined lower operating limit would predictably detect an open switch, failed control signal, disconnected laser, or other under-current condition in which the addressed laser does not draw the current expected from the commanded control signal, thereby permitting the safety system to assert a fault and place the transmitter in a safe state.
Regarding claim 10, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for eye safety comprises comparing the drive voltage to a predetermined low voltage value (Figs. 3-5, para 63, 86, a local energy monitor (306) may determine that a safety condition is violated when monitored voltage across a local energy storage (305) exceeds or is below a safety threshold voltage).
Regarding claim 11, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for eye safety comprises comparing the drive voltage to a predetermined high voltage value (Figs. 3-5, para 63, 86, a local energy monitor (306) may determine that a safety condition is violated when monitored voltage across a local energy storage (305) exceeds or is below a safety threshold voltage).
Regarding claim 12, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for eye safety comprises comparing the drive current to a predetermined high current value.
Milgrome teaches that each laser-control switch controls the amount of current conducted through its respective laser and that optical-pulse power is controlled by the magnitude of current conducted through the laser diode. Milgrome further recognizes that the discharge switch or laser-control signal may fail. See Fig. 4, para 75, and claims 23–24. PHY1076-01 teaches that the Tx Bias ADC samples the actual laser-bias current, identifies a maximum bias-current operating value of 100 mA, and provides safety circuitry that detects faults involving the APC loop or bias current and disables the transmitter. See Sections 3.4.3, 4.3, and 4.4, pages 7, 17, and 19.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to sample the laser drive current and compare the sampled current with a predetermined upper current limit. Milgrome teaches that laser optical power is controlled by drive current magnitude and that a switch or control signal may fail, while PHY1076-01 teaches actual bias-current measurement, a known maximum operating current, and bias-current fault protection. The modification would predictably detect a shorted switch, stuck-on control signal, or other over-current condition capable of producing excessive optical output and would permit the transmitter to be disabled before the condition violates eye-safety requirements.
Regarding claim 17, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the drive voltage is a high side drive voltage (Fig. 4, para 71-72; an electrical switch (SCI) may be closed to commonly increase voltage on each anode terminal of laser diodes (DLl-DLn), and one or more laser enable signals may be selectively applied to one or more electrical switches (SDL1-SDLn) each connected to respective cathode terminals of the laser diodes (DLI-DLn) so that each laser diode (DLl -DLn) may be selectively energized by conducting current from its anode terminal to its cathode terminal).
Regarding claim 18, Milgrome in view of PHY1076-01, teaches the method of claim 1 wherein the drive voltage is a low side drive voltage (Fig. 4, para 71-72; an electrical switch (SCI) may be closed to commonly increase voltage on each anode terminal of laser diodes (DLl-DLn), and one or more laser enable signals may be selectively applied to one or more electrical switches (SDL1-SDLn) each connected to respective cathode terminals of the laser diodes (DLI-DLn) so that each laser diode (DLl -DLn) may be selectively energized by conducting current from its anode terminal to its cathode terminal).
Regarding claim 20, Milgrome in view of PHY1076-01, teaches the method of claim 19 wherein the laser array has at least two lasers that can be operated independently (Figs. 3-4, para 62-71; an electro optical modulator (303) may include any suitable number of lasers, for example, 1-64 lasers, (DLl-DLn) that can be selectively energized.).
Regarding claim 21, Milgrome in view of PHY1076-01, teaches the method of claim 1 further comprising reporting a severity of the fault condition to the host.
Milgrome teaches monitoring a laser-operating condition, generating safety-alarm signal 308/408 when the monitored condition violates a safety threshold, and providing the alarm to external control device 350/450, which may disable energy transfer or laser operation. See Figs. 3–4 and para 63- 64, 74- 75. PHY1076-01 teaches that the MCU maintains and reports alarms and warnings to the host and that, when an alarm is triggered, the MCU sets HostSFTtxfault, causing the fault to be reported through the TX_FAULT pin and STAT_CON register, after which the host may disable the laser by asserting Soft Tx Disable. See Sections 4.4.2 and 5, pages 20 and 22. The warning and alarm classifications indicate different levels of seriousness, with the alarm classification initiating the fault reporting and hostaction path. Accordingly, reporting whether the condition is classified as a warning or an alarm constitutes reporting a severity of the fault condition.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to classify and report a detected laser-operating condition as a warning or an alarm because the different classifications communicate the relative seriousness and urgency of the condition to the host. Reporting the severity would permit the host to select a response proportional to the detected condition, such as continuing operation while monitoring a warning condition or disabling the affected laser in response to an alarm condition, thereby improving fault management while avoiding unnecessary shutdowns.
Regarding claim 22, Milgrome in view of PHY1076-01, teaches the method of claim 1 further comprising performing additional diagnostics in response to the fault condition.
Milgrome teaches detecting an abnormal laser-operating condition, generating safety-alarm signal 308/408, and communicating the alarm to external control device 350/450, which may be a programmable processing device that controls or disables laser operation. See Figs. 3- 4 and para 63- 64. PHY1076-01 teaches a digital-diagnostic process that obtains real-time transmitter measurements, including Tx Bias current, Tx Output Power, temperature, and supply voltage, evaluates transmitter faults, stores diagnostic status, and updates the STAT_CON register for access by the host. PHY1076-01 further teaches reporting a detected fault through the TX_FAULT pin and STAT_CON register and maintaining and reporting associated alarms and warnings.See Sections 4.4.2 and 5.3.1.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, so that the host performs additional diagnostics in response to the reported laser fault. Reading and evaluating transmitter bias current, optical output power, temperature, supply voltage, and related status information would permit the host to distinguish among possible causes of the fault, such as a failed laser, abnormal drive current, power-supply condition, or thermal condition, and thereby select an appropriate corrective action rather than indiscriminately disabling the entire transmitter.
Regarding claim 26, Milgrome in view of PHY1076-01, teaches the method of claim 1 further comprising reporting health status to a host that takes an action on the LiDAR transmitter in response to the health status.
Milgrome teaches that local energy monitor 306 monitors an electrical operating condition of the laser transmitter, compares the monitored voltage with a safety threshold, and generates safety alarm signal 308 indicating whether the transmitter is operating within a safe condition. Milgrome further teaches that external control device 350 uses the alarm condition to control energy transfer or disable laser operation. See Fig. 3 and 63-64. PHY1076-01 teaches reporting real-time laser health information to a host, including Tx Bias current and Tx Output Power, and teaches maintaining and reporting alarms and warnings through the TX_FAULT pin and STAT_CON register. PHY1076-01 further teaches that the host may take responsive action by asserting Soft Tx Disable to disable the laser. See Sections 4.4.2 and 5.3.1, pages 20 and 28.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to report monitored laser health information, including laser-bias current, transmitter output power, and associated alarm or warning status, to a host. Providing the monitored health status to the host would permit the host to determine whether the transmitter is operating normally or under a degraded or faulted condition and to take an appropriate protective action, such as disabling the affected laser or transmitter, thereby improving diagnostic capability and operational safety.
Regarding claim 27, Milgrome teaches a method for detecting a fault condition in a light detection and ranging (LiDAR) transmitter, the method comprising:
a) generating a control signal that comprises an address and desired drive voltage information for a laser in a laser array (para 82-85, Fig. 3. Control device 350 sets the power for the laser array and addresses each laser to be in an "on" or "off" state. Para 76 discloses multiple channels. Each channel has its own modulator and is, therefore, independent. Furthermore, each channel has own laser diode. Therefore, each diode is addressable.);
b) generating a drive signal for the laser in the laser array in response to the generated control signal and applying the generated drive signal to a contact associated with that address of the laser array, thereby energizing the laser at a desired output power for a desired time (Figs. 3 and 5);
c) determining (at a predetermined delay time after the generating of the control signal,) if the drive signal has a parameter with a value that is outside a threshold range for functional safety (Fig. 5B, monitor the voltage….) by capturing a state of the drive signal during energization of the laser (Milgrome teaches that laser-control signals 418-420 are placed in an enable state to connect corresponding discharge switches SDL1-SDLn, thereby permitting current to pass through and energize corresponding laser diodes DL1-DLn. During those operations, local energy monitor 414 monitors, i.e., captures, the voltage at internal node 404. See Fig. 5B and paragraphs para 91- 93. Internal node 404 is directly connected to the laser diodes, and the voltage at node 404, together with the conduction resistance and duration of the corresponding switch, determines the current through and optical power of the energized laser. Thus, the monitored node-404 voltage represents a captured state of the actual electrical drive signal during laser energization. See Fig. 4 and para 74-77. Milgrome further teaches comparator U1 comparing the captured voltage at node 404 with threshold voltage 422 supplied by control device 450 and generating safety-alarm signal 408 as the comparison result. The comparison result indicates whether the laser is operating in an acceptable or faulted health condition. See Fig. 4 and para 74- 75).
Milgrome fails to explicitly teach
c) determining, at a predetermined delay time after the generating of the control signal, if the drive signal has a parameter with a value that is outside a threshold range for functional safety by comparing the captured state to a desired state corresponding to the control signal;
d) storing, at the predetermined delay time after the generating of the control signal, the address and a fault condition if the parameter has the value outside the threshold range for functional safety.
e) reporting the address and the fault condition to a host that takes an action on the LiDAR transmitter in response to the fault condition.
As described above, Milgrome teaches capturing an actual electrical state associated with the drive of an energized laser diode and comparing that captured state with a reference threshold supplied by control device 450. Milgrome fails to explicitly teach that the comparison reference is a desired state corresponding to the generated control signal and further fails to explicitly teach performing the comparison after the recited predetermined delay.
PHY1076-01 teaches a laser driver having an analog mean-power control loop digitally programmed through the Mean Power DAC. Actual mean laser power is captured through the monitor-photodiode current, and actual laser-bias current is sampled using the Tx Bias ADC. See Section 4.3, Table 3, and Fig. 15, page 17.
PHY1076-01 further teaches that the actual monitor-photodiode current is compared with a reference current controlled by the programmed tx_power_set value. Thus, the actual feedback represents the captured state of the energized laser, while the reference controlled by tx_power_set represents the desired state corresponding to the programmed control value. See Section 4.3.1 and Fig. 15, page 17.
PHY1076-01 also teaches that, after the laser is turned on, the bias-control loop is allowed to settle for predetermined time tsettle before the safety-control loop is enabled. Therefore, the health or fault determination is performed after expiration of a predetermined delay following activation of the laser-control operation. See Section 4.4.1, pages 19-20; see also Section 3.4.3, page 7, identifying settling times of 5 ms and 500 µs.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Milgrome, as taught by PHY1076-01, so that the actual state of the laser drive signal captured during energization is compared with a desired reference state established by the generated control signal after expiration of a predetermined settling interval. PHY1076-01 teaches comparing actual laser operation feedback with a reference controlled by the programmed laser control value and delaying the safety comparison until the control loop has settled. The modification would have predictably enabled Milgrome’s safety system to determine whether the actual laser drive condition corresponds to the commanded drive condition, while avoiding false fault determinations caused by transient ramp-up or settling conditions. A person of ordinary skill would have recognized that PHY1076-01’s command dependent reference technique could likewise be applied to Milgrome’s electrical monitoring comparator by deriving the reference voltage or current from the commanded drive-voltage/current information, thereby permitting direct comparison of Milgrome’s captured electrical drive state with the expected electrical state for the selected laser.
Milgrome in para 63 teaches the safety alarm signal 308 may remain asserted until any suitable safety criteria are met (e.g., until a reset signal is received, until the voltage of internal node satisfies the safety condition, etc.). It would have been obvious to one of ordinary skill in the art to implement the retained safety-alarm condition using a latch, register, or other memory element so that the detected error condition remains available to controller 350 until the prescribed reset or recovery condition occurs. Such storage would permit the controller to prevent further laser operation and maintain the transmitter in a safe state after the transient condition that initially produced the fault may no longer be present.
Milgrome teaches a method for detecting a fault condition in a LiDAR transmitter, including generating a control signal comprising an address and desired drive voltage/current information for a laser in a laser array, generating and applying a corresponding drive signal to energize the addressed laser, monitoring a drive or bias parameter relative to a functional safety threshold, and asserting and maintaining a fault or alarm condition associated with the addressed laser when the threshold is violated.
While Milgrome does not explicitly describe delaying the timing of the fault determination and storage relative to generation of the control signal, the PHY1076-01 laser driver explicitly teaches a predetermined delay following a laser enable or turn-on event before safety monitoring is performed. Specifically, PHY1076-01 states that “when the laser is turned on, during power up or after a fault, there will be a short period during which the bias control loop is allowed to settle (t_settle) before the safety control loop circuit is enabled” (see Section 4.4.1, “Fault Management,” pages 19-20; see also Section 3.4.3, “Bias Loop Settling Time (t_settle),” page 7). Thus, determination of whether a monitored drive or bias parameter is outside a functional safety threshold is performed only after expiration of the predetermined settling time, rather than in real time. PHY1076-01 further teaches that operation outside fixed eye-safety limits cause a safety fault to be asserted (see Section 3.4.4, “Eye Safety Internal Fixed Limits,” page 8) and that detected safety faults are latched and maintained until reset (see Section 4.4.1, “Fault Management,” page 19), which constitutes storing the fault condition. It would have been obvious to one of ordinary skill in the art to incorporate this known delayed-enable safety monitoring and fault-latching technique into Milgrome’s addressed LiDAR fault-detection method so that the determination of whether the drive signal parameter is outside the functional safety threshold and the storing of the address and fault condition are performed at the predetermined delay time after generating the control signal, as recited in claim 27, in order to avoid false fault indications during transient ramp-up conditions. It would further have been obvious to store the known address of the laser being energized together with the retained fault condition because associating the fault with the affected laser would permit the controller or host to identify the failed channel and take laser specific corrective action.
Milgrome teaches that each laser control signal 318- 320 corresponds to and selectively energizes a respective laser diode. Therefore, when the controller asserts a particular laser control signal, the controller knows the identity or address of the laser being operated. Milgrome further teaches that local energy monitor 306 measures node voltage and generates safety alarm signal 308 when the measured voltage violates the safety threshold. See Fig. 3 and para 62- 63.
Milgrome also teaches that the safety alarm signal is provided to control circuitry and may be used by control device 350, which is a programmable processing device or digital logic circuit external to the TOSA, to de-assert the energy control signal or the laser control signals when safe operating conditions are not met. Thus, Milgrome teaches communicating the detected fault condition to an external controller that takes protective action on the transmitter by disabling further energy transfer or laser operation. See Fig. 3 and para 64. Milgrome additionally teaches that the external controller supplies the respective laser-enable signals controlling the individual laser channels. See Fig. 4 and para 70- 72.
PHY1076-01 teaches the claimed host-reporting operation. Section 4.4.2, “MCU and Host Fault Management,” page 20, teaches that the MCU maintains and reports alarms and warnings, reports a detected fault through the TX_FAULT pin and STAT_CON register, and that the MCU or host may respond to the reported fault by asserting Soft Tx Disable to disable the laser.
Milgrome in view of PHY1076-01 does not explicitly teach that a laser address is included in the fault report. However, Milgrome individually operates the laser diodes using respective laser-control signals, such that the controller already knows the identity of the laser being energized when the fault is detected.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to report the detected fault condition to a host and permit the host to take protective action by disabling laser operation. It would further have been obvious to include the known address or identifier of the laser being energized with the reported fault condition because Milgrome individually controls respective laser diodes using corresponding laser control signals, and reporting the affected laser identifier would permit the host to identify the particular faulty laser channel and take targeted corrective, diagnostic, servicing, or operating action.
Regarding claim 28, Milgrome in view of PHY1076-01, teaches the method of claim 27 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for functional safety comprises comparing drive current of the drive signal to a predetermined low current value.
Milgrome teaches that each laser-control switch controls the amount of current conducted through its corresponding laser, that laser-pulse power depends on the magnitude of current conducted through the laser diode, and that a discharge switch or laser-control signal may fail. See Fig. 4, para 75, and claims 23-24. PHY1076-01 teaches that the Tx Bias ADC samples the actual laser-bias current, identifies a normal operating range beginning at 0.5 mA and an off-state current of 10 µA, and provides safety circuitry that detects faults involving the APC loop or bias current. See Sections 3.4.3, 4.3, and 4.4, pages 7, 17, and 19.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to sample the laser drive current and compare the sampled current with a predetermined lower operating limit. Milgrome recognizes that the laser switch or control signal may fail, while PHY1076-01 teaches actual bias-current measurement, known energized and disabled current levels, and bias-current fault protection. Comparing the measured current with a predetermined low-current value would predictably detect an open switch, disconnected laser, failed control signal, or other under-current condition indicating that the addressed laser is not functioning as commanded.
Regarding claim 29, Milgrome in view of PHY1076-01, teaches the method of claim 27 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for functional safety comprises comparing the drive voltage to a predetermined low voltage value (Milgrome, Figs. 3-5, para 63, 86, a local energy monitor (306) may determine that a safety condition is violated when monitored voltage across a local energy storage (305) exceeds or is below a safety threshold voltage).
Regarding claim 30, Milgrome in view of PHY1076-01, teaches the method of claim 27 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for functional safety comprises comparing the drive voltage to a predetermined high voltage value.
Milgrome teaches that the laser diode anodes are coupled to internal node 304/404 and that the voltage at the laser anode controls the current through the laser diode and the resulting optical pulse power. Thus, the voltage at node 304/404 constitutes the laser drive voltage. Milgrome further teaches that local energy monitor 306 and comparator U1 compare the monitored voltage at node 304/404 with safety-threshold voltage 322/422 and detect a fault when the monitored voltage rises above the threshold voltage, indicating excessive charging or delivery of power. See Figs. 3–5 and para 63, 66, 74- 75, and 86. The supplied safety threshold voltage constitutes the predetermined high voltage value. Milgrome additionally teaches responding to the detected high-voltage condition by disabling further energy delivery or disabling the laser-control signals, thereby protecting functional safety.
Regarding claim 31, Milgrome in view of PHY1076-01, teaches the method of claim 27 wherein the determining if the drive signal has a parameter with a value that is outside a threshold range for functional safety comprises comparing drive current of the drive signal to a predetermined high current value.
Milgrome teaches that each laser control switch controls the amount of current conducted through its corresponding laser diode, that optical-pulse power is controlled by the magnitude of that current, and that the discharge switch or laser control signal may fail. See Fig. 4, para 75, and claims 23–24. PHY1076-01 teaches that the Tx Bias ADC samples the actual laser-bias current, identifies an upper bias-current operating value of 100 mA, and provides safety monitors that detect faults involving bias current and shut off the transmitter currents while asserting TX_FAULT. See Sections 3.4.3, 4.3, and 4.4, pages 7, 17, and 19.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to measure the laser drive current and compare the measured current with a predetermined upper operating limit. Milgrome teaches that laser output power depends on drive current magnitude and that the switch or control signal may fail, while PHY1076-01 teaches actual bias-current measurement, a known maximum operating current value, and protective action in response to a bias-current fault. The modification would predictably detect an over current condition caused by a shorted switch, stuck on control signal, or driver malfunction before the condition damages the transmitter or compromises functional safety.
Regarding claim 32, Milgrome in view of PHY1076-01, teaches the method of claim 27 wherein the drive voltage is a high side drive voltage (Milgrome, Fig. 4, para 71-72; (DLl-DLn), and one or more laser enable signals may be selectively applied to one or more electrical switches (SDL1-SDLn) each connected to respective cathode terminals of the laser diodes (DLI-DLn) so that each laser diode (DLl -DLn) may be selectively energized by conducting current from its anode terminal to its cathode terminal).
Regarding claim 33, Milgrome in view of PHY1076-01, teaches the method of claim 27 wherein the drive voltage is a low side drive voltage (Milgrome, Fig. 4, para 71-72; an electrical switch (SCI) may be closed to commonly increase voltage on each anode terminal of laser diodes (DLl-DLn), and one or more laser enable signals may be selectively applied to one or more electrical switches (SDL1-SDLn) each connected to respective cathode terminals of the laser diodes (DLI-DLn) so that each laser diode (DLl -DLn) may be selectively energized by conducting current from its anode terminal to its cathode terminal).
Regarding claim 35, Milgrome in view of PHY1076-01, teaches the method of claim 34 wherein the laser array has at least two lasers that can be operated independently (Milgrome, Figs. 3-4, para 62-71; an electro optical modulator (303) may include any suitable number of lasers, for example, 1-64 lasers (DLl-DLn) that can be selectively energized.).
Regarding claim 36, Milgrome in view of PHY1076-01, teaches the method of claim 27 further comprising reporting a severity of the fault condition to the host.
Milgrome teaches detecting a functional-safety fault when monitored voltage violates a safety threshold, generating safety-alarm signal 308/408, and providing the alarm to external control device 350/450, which may disable energy transfer or laser operation. See Figs. 3–4 para 63- 64, 74-75. Milgrome does not explicitly teach reporting different severity levels. PHY1076-01 teaches an SFF-8472-compliant diagnostic system in which the MCU maintains and reports alarms and warnings, reports fault information through the TX_FAULT pin and STAT_CON register, and permits the host to take responsive action by asserting Soft Tx Disable. See Sections 4.4.2 and 5, pages 20 and 22. Reporting whether the detected condition is an alarm or a warning constitutes reporting the severity of the fault condition.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to classify and report a detected functional-safety condition as an alarm or a warning because those classifications communicate the relative urgency or seriousness of the detected condition to the host. Reporting severity would permit the host to select a response appropriate to the condition, such as performing diagnostics or adjusting operation for a warning condition while immediately disabling the affected laser or transmitter for a more serious alarm condition, thereby improving functional-safety management and avoiding unnecessary shutdown for less serious deviations.
Regarding claim 37, Milgrome in view of PHY1076-01, teaches the method of claim 27 further comprising performing additional diagnostics in response to the fault condition Milgrome teaches detecting an abnormal laser-operating condition, generating safety-alarm signal 308/408, and communicating the alarm to external control device 350/450, which may be a programmable processing device that controls or disables laser operation. See Figs. 3- 4 and para 63- 64. PHY1076-01 teaches a digital-diagnostic process that obtains real-time transmitter measurements, including Tx Bias current, Tx Output Power, temperature, and supply voltage, evaluates transmitter faults, stores diagnostic status, and updates the STAT_CON register for access by the host. PHY1076-01 further teaches reporting a detected fault through the TX_FAULT pin and STAT_CON register and maintaining and reporting associated alarms and warnings.See Sections 4.4.2 and 5.3.1.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, so that the host performs additional diagnostics in response to the reported laser fault. Reading and evaluating transmitter bias current, optical output power, temperature, supply voltage, and related status information would permit the host to distinguish among possible causes of the fault, such as a failed laser, abnormal drive current, power-supply condition, or thermal condition, and thereby select an appropriate corrective action rather than indiscriminately disabling the entire transmitter.
Regarding claim 41, Milgrome in view of PHY1076-01, teaches the method of claim 27 further comprising reporting health status to a host that takes an action on the LiDAR transmitter in response to the health status.
Milgrome teaches that local energy monitor 306 monitors an electrical operating condition of the laser transmitter, compares the monitored voltage with a safety threshold, and generates safety-alarm signal 308 indicating whether the transmitter is operating within an acceptable condition. Milgrome further teaches that external control device 350 may respond to the alarm by disabling energy transfer or laser operation. See Fig. 3 and para 63-64. PHY1076-01 teaches providing real-time transmitter-health information to a host, including Tx Bias current and Tx Output Power, and maintaining and reporting alarms and warnings through the TX_FAULT pin and STAT_CON register. PHY1076-01 further teaches that the host may respond to the reported status by asserting Soft Tx Disable to disable the laser. See Sections 4.4.2 and 5.3.1, pages 20 and 28.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to report monitored laser health information, including bias current, transmitter output power, and associated alarm or warning status, to a host. Providing such health status to the host would permit the host to distinguish normal, degraded, and faulted operating conditions and to take an appropriate functional-safety action, such as disabling the affected laser or transmitter, thereby preventing continued operation of a malfunctioning laser channel.
Regarding claim 42, Milgrome teaches a method for detecting a health condition (Para 67. Health condition may refer to a component's internal condition and it also indicates whether the component is performing as expected, or failed) in a light detection and ranging (LiDAR) transmitter, the method comprising:
a) generating a control signal that comprises an address and desired drive voltage information for a laser in a laser array (para 82-85, Fig. 3. Control device 350 sets the power for the laser array and addresses each laser to be in an "on" or "off" state. Para 76 discloses multiple channels. Each channel has its own modulator and is, therefore, independent. Furthermore, each channel has own laser diode. Therefore, each diode is addressable.);
b) determining, (at a predetermined delay time after the generating of the control signal), a value for a health condition of the laser in the laser array ((Fig. 5B, monitor the voltage…. See also, para 67) by capturing a state of the drive signal during energization of the laser (Milgrome teaches that laser-control signals 418-420 are placed in an enable state to connect corresponding discharge switches SDL1-SDLn, thereby permitting current to pass through and energize corresponding laser diodes DL1-DLn. During those operations, local energy monitor 414 monitors, i.e., captures, the voltage at internal node 404. See Fig. 5B and paragraphs para 91- 93. Internal node 404 is directly connected to the laser diodes, and the voltage at node 404, together with the conduction resistance and duration of the corresponding switch, determines the current through and optical power of the energized laser. Thus, the monitored node-404 voltage represents a captured state of the actual electrical drive signal during laser energization. See Fig. 4 and para 74-77. Milgrome further teaches comparator U1 comparing the captured voltage at node 404 with threshold voltage 422 supplied by control device 450 and generating safety-alarm signal 408 as the comparison result. The comparison result indicates whether the laser is operating in an acceptable or faulted health condition. See Fig. 4 and para 74- 75).
Milgrome fails to explicitly teach
b) determining, at a predetermined delay time after the generating of the control signal, a value for a health condition of the laser in the laser array by comparing the captured state to a desired state corresponding to the control signal;
c) storing the address and the value of the health condition if the value is outside a threshold range for functional safety;
d) reporting the address and the health condition to a host that takes an action on the LiDAR transmitter in response to the health condition.
As described above, Milgrome teaches capturing an actual electrical state associated with the drive of an energized laser diode and comparing that captured state with a reference threshold supplied by control device 450. Milgrome fails to explicitly teach that the comparison reference is a desired state corresponding to the generated control signal and further fails to explicitly teach performing the comparison after the recited predetermined delay.
PHY1076-01 teaches a laser driver having an analog mean-power control loop digitally programmed through the Mean Power DAC. Actual mean laser power is captured through the monitor-photodiode current, and actual laser-bias current is sampled using the Tx Bias ADC. See Section 4.3, Table 3, and Fig. 15, page 17.
PHY1076-01 further teaches that the actual monitor-photodiode current is compared with a reference current controlled by the programmed tx_power_set value. Thus, the actual feedback represents the captured state of the energized laser, while the reference controlled by tx_power_set represents the desired state corresponding to the programmed control value. See Section 4.3.1 and Fig. 15, page 17.
PHY1076-01 also teaches that, after the laser is turned on, the bias-control loop is allowed to settle for predetermined time tsettle before the safety-control loop is enabled. Therefore, the health or fault determination is performed after expiration of a predetermined delay following activation of the laser-control operation. See Section 4.4.1, pages 19-20; see also Section 3.4.3, page 7, identifying settling times of 5 ms and 500 µs.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Milgrome, as taught by PHY1076-01, so that the actual state of the laser drive signal captured during energization is compared with a desired reference state established by the generated control signal after expiration of a predetermined settling interval. PHY1076-01 teaches comparing actual laser operation feedback with a reference controlled by the programmed laser control value and delaying the safety comparison until the control loop has settled. The modification would have predictably enabled Milgrome’s safety system to determine whether the actual laser drive condition corresponds to the commanded drive condition, while avoiding false fault determinations caused by transient ramp-up or settling conditions. A person of ordinary skill would have recognized that PHY1076-01’s command dependent reference technique could likewise be applied to Milgrome’s electrical monitoring comparator by deriving the reference voltage or current from the commanded drive-voltage/current information, thereby permitting direct comparison of Milgrome’s captured electrical drive state with the expected electrical state for the selected laser.
Milgrome teaches in Figs. 3-5, para 54-64, 67 “a local energy monitor (306) may monitor voltage that a local energy storage (305) provides to each laser diodes (DLl-DLn) and trigger a safety alarm signal (308) when the monitored voltage violates a safety condition related to a safety threshold voltage, wherein the safety condition may be defined as an expected operating condition meeting regulated eye safety standards; and an energy rate limiter (302) may terminate an energy transfer from a power supply to the local energy storage (305) in response to the safety alarm signal (308)”);
Milgrome in para 63 also teaches the safety alarm signal 308 may remain asserted until any suitable safety criteria are met (e.g., until a reset signal is received, until the voltage of internal node satisfies the safety condition, etc.). It would have been obvious to one of ordinary skill in the art to implement the retained safety-alarm condition using a latch, register, or other memory element so that the detected error condition remains available to controller 350 until the prescribed reset or recovery condition occurs. Such storage would permit the controller to prevent further laser operation and maintain the transmitter in a safe state after the transient condition that initially produced the fault may no longer be present. It would further have been obvious to store the known address of the laser being energized together with the retained fault condition because associating the fault with the affected laser would permit the controller or host to identify the failed channel and take laser specific corrective action.
Milgrome teaches a method for detecting a health condition in a LiDAR transmitter, including generating a control signal comprising an address and desired drive voltage information for a laser in a laser array, monitoring laser operating parameters to determine a health or safety condition, asserting and retaining an indication of the health condition when a functional-safety threshold is violated, and reporting the address and health condition to a host that takes protective action on the LiDAR transmitter. While Milgrome does not explicitly describe delaying the timing of the health determination relative to generation of the control signal, the PHY1076-01 laser driver teaches a predetermined delay following a laser enable or turn-on event before safety monitoring is performed. Specifically, PHY1076-01 states that “when the laser is turned on, during power up or after a fault, there will be a short period during which the bias control loop is allowed to settle (t_settle) before the safety control loop circuit is enabled” (see Section 4.4.1, “Fault Management,” pages 19-20; see also Section 3.4.3, “Bias Loop Settling Time (t_settle),” page 7). Thus, determination of a laser health or safety condition value is performed only after expiration of the predetermined settling time, rather than in real time. PHY1076-01 further teaches that operation outside fixed functional-safety limits cause a safety fault to be asserted (see Section 3.4.4, “Eye Safety Internal Fixed Limits,” page 8) and that detected faults are latched and maintained until reset (see Section 4.4.1, “Fault Management,” page 19), which constitutes storing the value of the health condition. It would have been obvious to one of ordinary skill in the art to incorporate this known delayed-enable safety monitoring and fault-latching technique into Milgrome’s addressed LiDAR health-detection method so that the determination of the health condition value is performed at a predetermined delay time after generating the control signal and the address and health condition are stored when the value is outside a functional-safety threshold, as recited in claim 42, in order to avoid false health indications during transient ramp-up conditions. It would further have been obvious to store the known address of the laser being energized together with the retained fault condition because associating the fault with the affected laser would permit the controller or host to identify the failed channel and take laser specific corrective action.
Milgrome teaches that each laser control signal 318- 320 corresponds to and selectively energizes a respective laser diode. Therefore, when the controller asserts a particular laser control signal, the controller knows the identity or address of the laser being operated. Milgrome further teaches that local energy monitor 306 measures node voltage and generates safety alarm signal 308 when the measured voltage violates the safety threshold. See Fig. 3 and para 62- 63.
Milgrome also teaches that the safety alarm signal is provided to control circuitry and may be used by control device 350, which is a programmable processing device or digital logic circuit external to the TOSA, to de-assert the energy control signal or the laser control signals when safe operating conditions are not met. Thus, Milgrome teaches communicating the detected fault condition to an external controller that takes protective action on the transmitter by disabling further energy transfer or laser operation. See Fig. 3 and para 64. Milgrome additionally teaches that the external controller supplies the respective laser-enable signals controlling the individual laser channels. See Fig. 4 and para 70- 72.
PHY1076-01 teaches the claimed host-reporting operation. Section 4.4.2, “MCU and Host Fault Management,” page 20, teaches that the MCU maintains and reports alarms and warnings, reports a detected fault through the TX_FAULT pin and STAT_CON register, and that the MCU or host may respond to the reported fault by asserting Soft Tx Disable to disable the laser.
Milgrome in view of PHY1076-01 does not explicitly teach that a laser address is included in the fault report. However, Milgrome individually operates the laser diodes using respective laser-control signals, such that the controller already knows the identity of the laser being energized when the fault is detected.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by PHY1076-01, to report the detected fault condition to a host and permit the host to take protective action by disabling laser operation. It would further have been obvious to include the known address or identifier of the laser being energized with the reported fault condition because Milgrome individually controls respective laser diodes using corresponding laser control signals, and reporting the affected laser identifier would permit the host to identify the particular faulty laser channel and take targeted corrective, diagnostic, servicing, or operating action.
Claims 19, 34 are rejected under 35 U.S.C. 103 as being unpatentable over Milgrome et in view of PHY1076-01 and Mark J. Donovan (US 2020/0326425 A1, “Donovan”).
Regarding claim 19, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 1 wherein the laser array comprises a two-dimensional laser array.
Milgrome teaches electro-optical modulator 303/403 comprising multiple individually controllable laser diodes DL1–DLn, with respective control signals selectively energizing corresponding lasers. However, Milgrome in view of PHY1076-01, fails to explicitly teach that the plurality of lasers comprises a two-dimensional array.
Donovan explicitly teaches a solid-state LiDAR transmitter comprising a two-dimensional monolithic VCSEL array 300 having 256 separate laser emitters 302. Donovan teaches that the emitters are spaced in both a horizontal direction and a vertical direction and are arranged in rows and columns that may be electrically driven in a matrix-addressable manner. See Fig. 3 and Para 45-48. Donovan further teaches arranging a plurality of lasers into a two-dimensional matrix to permit individual or group control of the lasers while providing appropriate drive current, voltage, and timing.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by Donovan, to arrange Milgrome’s plurality of individually controlled lasers as a two-dimensional laser array. Donovan teaches that a two-dimensional matrix permits a large number of lasers to be individually addressed while maintaining a compact solid-state LiDAR transmitter and reducing the electrical-connection complexity associated with separately driving numerous lasers. The modification would predictably increase the number of addressable emission directions and field-of-view coverage while preserving Milgrome’s individual laser-control and safety-monitoring functions.
Regarding claim 34, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 27 wherein the laser array comprises a two-dimensional laser array.
Milgrome teaches electro-optical modulator 303/403 comprising multiple individually controllable laser diodes DL1–DLn, with respective control signals selectively energizing corresponding lasers. However, Milgrome in view of PHY1076-01, fails to explicitly teach that the plurality of lasers comprises a two-dimensional array.
Donovan explicitly teaches a solid-state LiDAR transmitter comprising a two-dimensional monolithic VCSEL array 300 having 256 separate laser emitters 302. Donovan teaches that the emitters are spaced in both a horizontal direction and a vertical direction and are arranged in rows and columns that may be electrically driven in a matrix-addressable manner. See Fig. 3 and Para 45-48. Donovan further teaches arranging a plurality of lasers into a two-dimensional matrix to permit individual or group control of the lasers while providing appropriate drive current, voltage, and timing.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by Donovan, to arrange Milgrome’s plurality of individually controlled lasers as a two-dimensional laser array. Donovan teaches that a two-dimensional matrix permits a large number of lasers to be individually addressed while maintaining a compact solid-state LiDAR transmitter and reducing the electrical-connection complexity associated with separately driving numerous lasers. The modification would predictably increase the number of addressable emission directions and field-of-view coverage while preserving Milgrome’s individual laser-control and safety-monitoring functions.
Claims 23-24, 38-39 are rejected under 35 U.S.C. 103 as being unpatentable over Milgrome et in view of PHY1076-01 and Mark J. Donovan (WO 2018/169758 A1, “Donovan”).
Regarding claim 23, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 1 wherein the host adapts operating parameters based on the fault condition.
As indicated above in claim 1, PHY1076-01 teaches reporting a detected transmitter fault through the TX_FAULT pin and STAT_CON register and teaches that the MCU or host may respond by asserting Soft Tx Disable to change the operating state of the laser. Donovan, Fig.5, para 51-52, teaches a system processor that generates instructions controlling whether and for how long lasers fire and teaches that laser-firing rules may be generated based on LiDAR operating parameters and may change based on output power, pulse width, and repetition rate. It would have been obvious to further modify Milgrome, as taught by Donovan, so that the host adapts one or more laser operating parameters in response to the reported fault because reducing power, pulse width, repetition rate, or disabling the affected laser would permit continued safe operation while preventing further operation under the detected unsafe condition.
Regarding claim 24, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 1 wherein the host alters the firing sequence based on the fault condition.
However, Donovan teaches that system processor 516 generates instructions specifying when and for how long lasers fire, that those instructions determine the firing-pattern type, and that stored firing rules may be generated or changed by the system processor based on operating conditions. Donovan also teaches selecting firing sequences and rules that determine which lasers may be fired simultaneously or sequentially. See Fig. 5 and para 37, 42-43, and 51-52. It would have been obvious to further modify Milgrome, as taught by Donovan, to alter the firing sequence in response to the reported fault by removing the affected laser from the sequence or assigning its firing interval to another functioning laser because doing so would avoid repeatedly energizing a faulty laser while preserving scan coverage, refresh rate, and eye-safe operation.
Regarding claim 38, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 27 wherein the host adapts operating parameters based on the fault condition.
As indicated above in claim 27, PHY1076-01 teaches reporting a detected transmitter fault through the TX_FAULT pin and STAT_CON register and teaches that the MCU or host may respond by asserting Soft Tx Disable to change the operating state of the laser. Donovan, Fig.5, para 51-52, teaches a system processor that generates instructions controlling whether and for how long lasers fire and teaches that laser-firing rules may be generated based on LiDAR operating parameters and may change based on output power, pulse width, and repetition rate. It would have been obvious to further modify Milgrome, as taught by Donovan, so that the host adapts one or more laser operating parameters in response to the reported fault because reducing power, pulse width, repetition rate, or disabling the affected laser would permit continued safe operation while preventing further operation under the detected unsafe condition.
Regarding claim 39, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 27 wherein the host alters the firing sequence based on the fault condition.
However, Donovan teaches that system processor 516 generates instructions specifying when and for how long lasers fire, that those instructions determine the firing-pattern type, and that stored firing rules may be generated or changed by the system processor based on operating conditions. Donovan also teaches selecting firing sequences and rules that determine which lasers may be fired simultaneously or sequentially. See Fig. 5 and para 37, 42-43, and 51-52. It would have been obvious to further modify Milgrome, as taught by Donovan, to alter the firing sequence in response to the reported fault by removing the affected laser from the sequence or assigning its firing interval to another functioning laser because doing so would avoid repeatedly energizing a faulty laser while preserving scan coverage, refresh rate, and eye-safe operation.
Claims 25, 40 are rejected under 35 U.S.C. 103 as being unpatentable over Milgrome et in view of PHY1076-01 and Pierre-Yves Droz (US 20190178974 A1, “Droz”).
Regarding claim 25, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 1 wherein the host alters the laser-to-pixel mapping based on the fault condition.
As described in claim 1, Milgrome teaches detecting a laser transmitter fault and providing safety alarm signal 308/408 to control device 350/450, which may disable energy transfer or individual laser control signals in response to the detected condition. PHY1076-01 further teaches reporting the fault to a host through the TX_FAULT pin and STAT_CON register, thereby providing the host with the fault information used to select a responsive action. Milgrome in view of PHY1076-01, fails to explicitly teach altering the laser-to-pixel mapping.
Droz teaches a LiDAR system that generates point-cloud data using reconfigurable spatial light-emission patterns and corresponding reconfigurable light detector arrangements. During normal operation, first and second sets of emitter devices operate with respective first and second sets of detector devices. When a fault is detected in one of the emitter or detector sets, the controller changes to a failsafe mode by selecting the remaining operative emitter set and causing the corresponding detector set to collect the reflected light data used to form the point cloud. Droz specifically teaches selecting the second emitter set when the fault occurred in the first emitter set, or vice versa (Para 4; Fig. 6; Claims 14-17).
By changing from the emitter and detector associations used during normal operation to the operative emitter set and its corresponding detector set after the fault, Droz changes which detector pixels are associated with the lasers used to generate the point cloud. This constitutes altering the laser-to-pixel mapping based on the fault condition.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by Droz, so that the host uses the reported address and fault condition to exclude the faulty laser channel and associate the remaining operative lasers with corresponding detector pixels. The modification would prevent pixels from being processed as though they contained valid returns from the faulty laser and would permit the LiDAR system to continue producing a reduced resolution but usable point cloud using the remaining functional emitter and detector channels.
Regarding claim 40, Milgrome in view of PHY1076-01, fails to explicitly teach the method of claim 27 wherein the host alters the laser-to-pixel mapping based on the fault condition.
As described in claim 27, Milgrome teaches detecting a laser transmitter fault and providing safety alarm signal 308/408 to control device 350/450, which may disable energy transfer or individual laser control signals in response to the detected condition. PHY1076-01 further teaches reporting the fault to a host through the TX_FAULT pin and STAT_CON register, thereby providing the host with the fault information used to select a responsive action. Milgrome in view of PHY1076-01, fails to explicitly teach altering the laser-to-pixel mapping.
Droz teaches a LiDAR system that generates point-cloud data using reconfigurable spatial light-emission patterns and corresponding reconfigurable light detector arrangements. During normal operation, first and second sets of emitter devices operate with respective first and second sets of detector devices. When a fault is detected in one of the emitter or detector sets, the controller changes to a failsafe mode by selecting the remaining operative emitter set and causing the corresponding detector set to collect the reflected light data used to form the point cloud. Droz specifically teaches selecting the second emitter set when the fault occurred in the first emitter set, or vice versa (Para 4; Fig. 6; Claims 14-17).
By changing from the emitter and detector associations used during normal operation to the operative emitter set and its corresponding detector set after the fault, Droz changes which detector pixels are associated with the lasers used to generate the point cloud. This constitutes altering the laser-to-pixel mapping based on the fault condition.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Milgrome, as taught by Droz, so that the host uses the reported address and fault condition to exclude the faulty laser channel and associate the remaining operative lasers with corresponding detector pixels. The modification would prevent pixels from being processed as though they contained valid returns from the faulty laser and would permit the LiDAR system to continue producing a reduced resolution but usable point cloud using the remaining functional emitter and detector channels.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Sato et al. (US 5511087 A), teaches method and Device for Controlling Semiconductor Laser
David S. Hall (WO 2011146523 A2), teaches high definition lidar system
Shatabda Saha (US 9753060 B2), teaches apparatus With Device with Fault Detection Protection
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