DETAILED ACTION
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 .
Priority
The following claimed benefit is acknowledged: The instant application, filed on 09/11/2023, claims foreign priority to JP Application No. 2022-197377, filed on 12/09/2022.
Information Disclosure Statement
The Information Disclosure Statements (lDS) submitted on 09/11/2023, 04/09/2024 and 05/14/2026 are in compliance with the provisions of 37 CFR 1.97 and have been considered.
Claim Objections
Claims 1-10 are objected to because of the following informalities:
Regarding claim 1, “an reset circuit” should read --a reset circuit--.
Regarding claim 3, “regardless of the output signal” should perhaps read --independently of the output signal--.
Regarding claim 6, “a voltage of the one end” should read --the voltage at the one end--.
Regarding claim 15, “receive” and “measure” should read --receives-- and –measures--.
Regarding claim 20, “regardless of the output signal” should perhaps read --independently of the output signal--.
Claims 2-20 are further objected to by virtue of dependency.
Appropriate correction is required.
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.
Claims 4-5, 8 and 13-20 are 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 4 recites “ambient light with uniform illuminance.” Although a term of degree is not indefinite per se, the Specification must provide a standard for measuring the degree, or the term must have an ascertainable meaning to one of ordinary skill in the art. See MPEP § 2173.05(b). Here, the Specification merely repeats the phrase “uniform illuminance” without defining the relevant area, measurement method, or permissible variation in illuminance. For example, the Specification contemplates both a single photodetection element and one- or two-dimensional arrays, but does not specify whether uniformity is evaluated across one element’s light-receiving surface, a selected group of elements, or the entire array, each of which may yield a different uniformity determination. Accordingly, it is unclear what degree of illuminance variation is encompassed by “uniform.”
Claim 5 is indefinite because the phrase “ambient light having sensitivity to the threshold” is unclear. It is not clear whether the claimed “sensitivity” refers to the ambient light, the photodetection element, the firing detection circuit, an occurrence rate of firing, or some other parameter. Ambient light does not ordinarily have “sensitivity” to a threshold. Therefore, the metes and bounds of the claimed firing detection are unclear.
Claim 8 is indefinite because the phrase “a comparison result between a signal of the one end of the photodetection element and the threshold” is unclear. Claim 8 depends from claim 7, which recites a current comparator that compares a current with a threshold current. However, claim 8 recites a “signal of the one end” and “the threshold,” without making clear whether the comparison is between a current and the threshold current of claim 7, a voltage and a threshold voltage, or some other signal and threshold. The further recitation that the threshold control circuit “controls the threshold” is likewise unclear because it is not clear which threshold is being controlled.
Claim 13 is indefinite because the phrase “a plurality of the photodetection elements” lacks clear antecedent basis. Claim 1 recites “a photodetection element,” but does not previously recite plural “photodetection elements.”
Claim 13 is also unclear because the phrase “the firing detection circuit is provided for each of the plurality of photodetection elements” appears to refer to the single firing detection circuit of claim 1, while also requiring a firing detection circuit for each photodetection element. It is therefore unclear whether one firing detection circuit is shared, or whether respective firing detection circuits are provided. The phrase “corresponding to the two or more photodetection elements to be shared” is also unclear because it is not clear what structure is “to be shared.”
Claim 14 is indefinite because the phrase “a plurality of the photodetection elements” lacks clear antecedent basis for the same reason discussed above with respect to claim 13.
Claim 14 is further indefinite because the selection circuit “selects any of the photodetection elements,” which is unclear as to whether the selection circuit selects one photodetection element, more than one photodetection element, or an arbitrary subset of photodetection elements.
Claim 14 also recites “the corresponding photodetection element groups,” but the claim previously introduces only singular “a photodetection element group.” Accordingly, it is unclear whether the firing detection circuit, monitor circuit, and threshold control circuit correspond to one photodetection element group or to a plurality of photodetection element groups.
Claim 5 is further rejected as being dependent on and failing to cure the deficiencies of rejected claim 4.
Claims 15-20 are rejected as being dependent on and failing to cure the deficiencies of rejected claim 14.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim 1 is rejected under 35 U.S.C. 102(a)(2) as being anticipated by Tsukuda (US 20230231060 A1).
Regarding claim 1, Tsukuda discloses a photodetection device (Fig. 2, photodetection circuit 142; ¶¶ 56-57) comprising: a photodetection element (Fig. 2, photodetection element 151; ¶ 58);
an reset circuit that sets one end of the photodetection element to a predetermined initialization voltage (Fig. 2, charging circuit 152 connected to the cathode of photodetection element 151; ¶¶ 58-59, charging circuit 152 “supplies a positive voltage to the cathode” to establish Geiger mode operation; Fig. 9 and ¶ 87, cathode voltage Vc recovers after avalanche multiplication, with the supplied pre-avalanche cathode voltage corresponding to the predetermined initialization voltage);
a firing detection circuit that detects firing of the photodetection element by comparing a voltage at the one end of the photodetection element or a current flowing through the one end with a threshold (Fig. 2, the comparison portion of input amplifier 154, as further detailed in Fig. 3A as inverter circuit 161; ¶¶ 62, 68, 70, 72-73, inverter circuit 161 receives cathode voltage Vc and switches output voltage Vs according to comparison with the reference voltage switching threshold; Fig. 10 and ¶ 89, drop of cathode voltage Vc is detected at first reference voltage Vref1);
a monitor circuit that monitors an output signal of the firing detection circuit (Fig. 2, state detecting circuit 155, as further detailed in Fig. 7; ¶¶ 63, 84-85, state detecting circuit 155 detects the voltage level of output signal Vs and produces output voltage Vo after a predetermined delay); and
a threshold control circuit that controls the threshold based on a monitor output of the monitor circuit (Fig. 3A, voltage control circuit 162; ¶¶ 71, 73, output voltage Vo of state detecting circuit 155 controls switching element 174 to increase or decrease the reference voltage switching threshold).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 2-3 are rejected under 35 U.S.C. 103 as being unpatentable over Tsukuda in view of Bodlovic (US 20150364635 A1).
Regarding claim 2, Tsukuda discloses the photodetection device of claim 1, and further discloses: wherein when the firing detection circuit detects firing (Fig. 3A, inverter circuit 161; ¶¶ 70, 72-73; Fig. 10 and ¶ 89, drop of cathode voltage Vc is detected at first reference voltage Vref1), the reset circuit returns the one end of the photodetection element to the initialization voltage (Fig. 2, charging circuit 152; ¶ 59, charging circuit 152 supplies the positive cathode voltage; Fig. 9 and ¶ 87, cathode voltage Vc gradually recovers after avalanche multiplication converges) […].
Tsukuda does not disclose: [the reset circuit returns the one end of the photodetection element to the initialization voltage] “based on the output signal of the firing detection circuit.” However, Bodlovic teaches the limitation, specifically, comparator 614 produces a firing detection output when firing occurs (¶ 63, “change in voltage causes the input to the comparator 614 to cross its switching threshold, generating a detect signal”), where the firing detection output initiates a quench and reset sequence (¶ 65, “detect signal from the comparator 614 is used to trigger the quench circuit 630 to quench the SPAD 607”), the sequence then operates reset switch 602 to restore the SPAD operating voltage, where the recharge raises the voltage at the SPAD cathode and “brings the voltage difference across the SPAD 607 to above the threshold voltage Vth, ready for the next avalanche event” (¶ 66). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the reset circuit of Tsukuda with the teachings of Bodlovic with a reasonable expectation for success in order to provide faster restoration of the SPAD operating voltage and reduce dead time (Bodlovic, ¶ 13).
Regarding claim 3, Tsukuda in view of Bodlovic teaches the photodetection device of claim 2, and further teaches: wherein when the firing detection circuit detects firing (Tsukuda, Fig. 3A, inverter circuit 161; ¶¶ 70, 72-73; Fig. 10 and ¶ 89, drop of cathode voltage Vc is detected at first reference voltage Vref1), the reset circuit returns the one end of the photodetection element to the initialization voltage (Tsukuda, Fig. 2, charging circuit 152; ¶ 59; Fig. 9 and ¶ 87, cathode voltage Vc gradually recovers after avalanche multiplication converges) regardless of the output signal of the firing detection circuit (Bodlovic, ¶ 12, passive voltage recovery results from the applied bias and the change in voltage drop across series resistor as avalanche current increases and then subsides, performed independently of the comparator’s detect signal). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the reset circuit of Tsukuda in view of Bodlovic with the further teachings of Bodlovic with a reasonable expectation of success in order to provide autonomous recovery of the photodetection element, yielding a photodetection device with greater operational reliability and lower circuit and control complexity.
Claims 4-5 are rejected under 35 U.S.C. 103 as being unpatentable over Tsukuda in view of Tsukuda2 (US 20230187462 A1).
Regarding claim 4, Tsukuda discloses the photodetection device of claim 1, and further discloses: wherein the firing detection circuit detects firing of the photodetection element (Fig. 2, input amplifier 154, as further detailed in Fig. 3A, inverter circuit 161; ¶¶ 62, 68, 70, 72-73, cathode voltage Vc is compared with the reference voltage switching threshold; ¶ 87, photon-induced avalanche multiplication causes Vc to drop; Fig. 10 and ¶ 89, the drop of Vc is detected at first reference voltage Vref1) […].
Tsukuda does not disclose: [the firing detection circuit detects firing of the photodetection element] “in a situation where the photodetection element is shielded from light or in a situation where ambient light with uniform illuminance is incident on the photodetection element.” However, Tsukuda2 teaches the limitation in ¶ 100 and Fig. 11. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the teachings of Tsukuda such that the firing detection circuit operated under the dark box condition as taught by Tsukuda2 with a reasonable expectation of success in order to determine dark count and impact on crosstalk performance (Tsukuda2, ¶¶ 100-102), yielding a photodetection device with improved noise characterization and calibration accuracy, providing for greater reliability in threshold setting and photon event discrimination.
Regarding claim 5, Tsukuda in view of Tsukuda2 teaches the photodetection device of claim 4, and further teaches: wherein the firing detection circuit detects firing (Tsukuda, Fig. 2, input amplifier 154, as further detailed in Fig. 3A, inverter circuit 161; ¶¶ 62, 70, 73, voltage level Vs switches according to cathode voltage Vc and the reference voltage threshold; Fig. 10 and ¶ 89, the drop of Vc is detected at Vref1) by a dark count or ambient light having sensitivity to the threshold (Tsukuda2, ¶¶ 99-101, the comparator detects firing by dark count events, and the detected occurrence rate changes according to the threshold). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the teachings of Tsukuda in view of Tsukuda2 with the dark count threshold sweep technique as further taught by Tsukuda2 with a reasonable expectation of success in order to establish an operating threshold informed by noise behavior (Tsukuda2, ¶¶ 99-102), yielding a photodetection device with improved dark noise discrimination, photon counting accuracy, and measurement confidence and reliability.
Claims 9-11 are rejected under 35 U.S.C. 103 as being unpatentable over Tsukuda in view of Dubey (“Discriminator Threshold Selection Logic to Improve Signal to Noise Ratio in Photon Counting,” published 2010)1.
Regarding claim 9, Tsukuda discloses the photodetection device of claim 1, and further discloses: wherein the firing detection circuit outputs a pulse signal (Fig. 3A, inverter circuit 161 outputs voltage Vs; ¶¶ 70, 72-73) [1: …], and the threshold control circuit controls the threshold (Fig. 3A, voltage control circuit 162 changes the reference voltage threshold; ¶¶ 71, 73) [2: …].
Tsukuda does not disclose: (1) [the firing detection circuit outputs a pulse signal] “having an occurrence rate according to the threshold”; and, (2) [the threshold control circuit controls the threshold] “based on the occurrence rate of the pulse signal.” However, Dubey teaches limitations. In particular, Dubey teaches that the firing detection discriminator outputs pulses according its discriminator threshold (Fig. 1, SRS high speed MCS having built-in discriminator; p. 64, the discriminator level determines “the voltage level above which the pulses would be delivered at the output”); the pulse signal having an occurrence rate according to the threshold (p. 64, §2.1, the pulses are “fed to the MCS for counting in specified time bins”; p. 69, “the number of photon counts counted by the counter greatly depends on discriminator threshold”); and threshold selection logic controls the discriminator threshold based on fixed-time pulse count (p. 65, §2.2, acquires count data throughout a specified threshold range and selects the threshold; p. 68, the selected threshold based on the portion of the count response having minimum variation). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the photodetection device of Tsukuda with the teachings of Dubey with a reasonable expectation of success in order to provide automatic threshold selection yielding a photodetection device with greater signal-to-noise ratio, photon counting efficiency, and measurement stability (Dubey, Abstract; pp. 64-65, 68-69).
Regarding claim 10, Tsukuda in view of Dubey teaches the photodetection device of claim 9, and further teaches: wherein the threshold control circuit continuously or stepwise changes the threshold (Dubey, p. 64, § 2.1, “acquires data in particular bin for the specified range of discriminator threshold,” where, p. 65, § 2.2, “data is acquired in specified discriminator steps”), and sets, in the firing detection circuit, the threshold when a variation amount of the occurrence rate of the pulse signal falls within a predetermined amount (Dubey, p. 65, § 2.2, acquires fixed-bin photon count data over the specified threshold range in the specified threshold steps, corresponding to the variation of pulse occurrence rate; Fig. 5, p. 68, identifies “almost stable counts” between -140 mV and -300 mV at a -1000 V detector supply and identifies the flat response as exhibiting “minimum variation of photon counts” with a change in threshold; Fig. 6 evaluates fluctuation quantitatively using the ratio of standard deviation to average count as a function of discriminator threshold; pp. 68-69, teaches selecting a critical discriminator value that produces minimum fluctuation and identifies a stable response after -150 mV for the -900 V and -1000 V operating conditions, corresponding to the occurrence rate variation falling within an acceptable or predetermined amount; p. 69, resulting selected thresholds are stored and read to represent the selected detector voltage, corresponding to setting the threshold when the criterion is satisfied). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the photodetection device of Tsukuda in view of Dubey with the additional teachings of Dubey with a reasonable expectation of success in order to automate selection of a stable operating threshold, yielding a photodetection device with improved measurement consistency and greater adaptability across varying operating conditions (Dubey, p. 65, §2.2; pp. 68-69).
Regarding claim 11, Tsukuda in view of Dubey teaches the photodetection device of claim 10, and further teaches: wherein the threshold control circuit sets the threshold to a median value of a control range of the threshold in which a variation amount of the occurrence rate of the pulse signal falls within the predetermined amount (Dubey, Fig. 5; p. 68, selects the “middle threshold value” to minimize count variation, corresponding to the median value of the control range in which occurrence rate variation satisfies the predetermined stability criterion). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the photodetection device of Tsukuda in view of Dubey with the additional teachings of Dubey with a reasonable expectation of success in order to select an operating point having greater margin within the stable threshold range, thereby yielding a photodetection device with improved robustness to drift, operational stability, and measurement reliability (Dubey, pp. 68-69).
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Tsukuda in view of Guo (US 20160182902 A1).
Regarding claim 13, Tsukuda discloses the photodetection device of claim 1, and further discloses: comprising a pixel array including a plurality of the photodetection elements arrayed in a one-dimensional or two-dimensional direction (¶ 86, “a pixel array in which the plurality of photodetection elements 151 is two-dimensionally arranged”), wherein [1: …], the firing detection circuit is provided for each of the plurality of photodetection elements (Fig. 2, photodetection circuit 142 corresponding to one pixel, with input amplifier 154 further detailed in Fig. 3A as inverter circuit 161; ¶ 57, a plurality of photodetection circuits 142 are provided according to the number of pixels; ¶¶ 62, 68-73, inverter circuit 161 compares cathode voltage Vc with its reference voltage threshold), and [2: …].
Tsukuda does not disclose: (1) “the monitor circuit and the threshold control circuit are shared by two or more of the photodetection elements”; and, (2) “the threshold control circuit controls the threshold of two or more of the firing detection circuits corresponding to the two or more photodetection elements to be shared.” However, Guo teaches a plurality of APD microcells, each having its own threshold comparison circuit, together with an array level monitor and controller. In particular, Guo teaches multiple microcells which form an array (¶ 20), wherein each microcell includes APD 204 and comparator 214, where comparator 214 compares output signal 213 with threshold voltage Vth and produces a logic output when that threshold is crossed (¶ 15). Guo further teaches an array-level shared monitor circuit (¶¶ 9, 17, 20, counter 310 monitors comparator derived output signals from multiple APD microcells) and shared threshold control circuit (¶ 18, controller 320 is shared by multiple APD microcells and, based on the output of shared counter 310, controls threshold Vth of the comparator circuits corresponding to those microcells). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the photodetection device of Tsukuda with the teachings of Guo with a reasonable expectation of success in order to manage microcells with particularly high dark count rates without requiring individual microcell addressing, thereby yielding a photodetection device with improved overall detector performance, higher fabrication yields, and lower manufacturing costs (Guo, ¶¶ 2, 18, 22).
Claims 1, 6-7 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Yeh (US 20230417908 A1) in view of Ichiyanagi (US 20180364340 A1).
Regarding claim 1, Yeh discloses a photodetection device (Fig. 1, sensing module 101, as further detailed in Fig. 2 by PCD circuit 21 and Fig. 3 by event counter 34; ¶¶ 23-24, 31, 35) comprising:
a photodetection element (Fig. 1, SPAD 111; ¶ 25);
an reset circuit that sets one end of the photodetection element to a predetermined initialization voltage (Fig. 1, recharge transistor 113; ¶ 26, transistor 113 “recharge[s] the voltage of the cathode of the SPAD 111 to the excessive bias voltage VEX”);
a firing detection circuit (Fig. 1, comparator 114; ¶ 27) [1: …];
a monitor circuit that monitors an output signal of the firing detection circuit (Fig. 2, PCD circuit 21, as further detailed in Fig. 3 by event counter 34; ¶¶ 32, 37, event counter 34 counts logical high pixel event signals oc and outputs count EC); and [2: …].
Yeh does not disclose: (1) [the firing detection circuit] “that detects firing of the photodetection element by comparing a voltage at the one end of the photodetection element or a current flowing through the one end with a threshold”; and, (2) “a threshold control circuit that controls the threshold based on a monitor output of the monitor circuit.” However, Ichiyanagi teaches limitation (1), where comparator 8 “compares the signal (voltage signal) output from the MUX 7c with a predetermined threshold” and outputs a high-level signal when the voltage signal exceeds the threshold (¶¶ 76-78; Fig. 4, comparator 8). Ichiyanagi further teaches limitation (2), where the second omitted limitation because maximum value detector 1b detects the “output frequency” of the comparator signal at each tentative threshold (¶ 89), threshold setting unit 1c selects real threshold Vt based on the monitored result (¶¶ 90, 93-94), and DAC 10 causes comparator 8 to change its threshold (¶¶ 82, 95). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the photodetection device of Yeh with the teachings of Ichiyanagi with a reasonable expectation of success in order to provide an adjustable threshold according to the level of the noise so as to distinguish reflected light signals from the background, thereby reducing false events caused by dark count and yielding improved distance measurement accuracy (Ichiyanagi, ¶¶ 81, 100-104).
Regarding claim 6, Yeh in view of Ichiyanagi teaches the photodetection device according to claim 1, and further teaches: wherein the firing detection circuit includes a voltage comparator (Yeh, Fig. 1, comparator 114 coupled to the cathode of SPAD 111; ¶ 27) [1: …], and outputs a binary signal indicating a comparison result (Yeh, Fig. 1, output oc; ¶¶ 23, 27, oc is logical high for a detected event), the monitor circuit includes a counter that monitors a number of signal changes of the binary signal (Yeh, Fig. 3, event counter 34; ¶ 37, counter 34 counts logical high oc signals; Fig. 4 and ¶¶ 39-40, oc signals are discrete impulses), and [2: …]. Yeh does not disclose: (1) [voltage comparator] “that compares a voltage of the one end of the photodetection element with a threshold voltage”; and, (2) “the threshold control circuit controls the threshold voltage based on the monitor output of the monitor circuit.” However, Ichiyanagi teaches limitation (1), where comparator 8 compares the SPAD receiver voltage signal with threshold voltage Vt and outputs a signal indicating the comparison result (¶¶ 76-79). Ichiyanagi further teaches limitation (2), where detector 1b monitors comparator output frequency, threshold setting unit 1c selects Vt based on that monitored output, and DAC 10 changes the comparator threshold (¶¶ 82, 89, 93-95). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the photodetection device of Yeh in view of Ichiyanagi with the additional teachings of Ichiyanagi with a reasonable expectation of success in order to change the comparator threshold according to noise level so that reflected light signals are reliably distinguished from noise (Ichiyanagi ¶¶ 81, 100-104).
Regarding claim 7, Yeh in view of Ichiyanagi teaches the photodetection device according to claim 1, and further teaches: wherein the firing detection circuit includes a current comparator that compares a current flowing through the one end of the photodetection element with a threshold current (Ichiyanagi, ¶ 112, “the comparator may compare the current signal corresponding to the current output from each SPAD group to the current threshold”), and the threshold control circuit controls the threshold current based on the monitor output of the monitor circuit (Ichiyanagi, ¶¶ 81-82, 89, 93-95, monitoring comparator output frequency and setting the comparator threshold from that monitored output). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the photodetection device of Yeh in view of Ichiyanagi with the additional teachings of Ichiyanagi. Ichiyanagi identifies voltage and current comparison as alternative implementations of the same noise discrimination function, and therefore adopting the firing detector in the current domain is motivated by enabling a noise-responsive threshold setting, yielding improved separation of reflected light signals from unwanted environmental noise (Ichiyanagi, ¶¶ 81, 100-104, 112).
Regarding claim 9, Yeh in view of Ichiyanagi teaches the photodetection device according to claim 1, and further teaches: wherein the firing detection circuit outputs a pulse signal (Yeh, Fig. 1, comparator output oc; ¶ 27, “logic-core voltage pulse”; Fig. 4 and ¶ 39, oc signals are “impulses”) having an occurrence rate according to the threshold (Ichiyanagi, ¶ 88, comparator 8 outputs pulse whenever a tentative threshold is exceeded; ¶ 89, detector 1b detects the pulse output frequency at each tentative threshold), and the threshold control circuit controls the threshold based on the occurrence rate of the pulse signal (Ichiyanagi, ¶¶ 90, 93-95, 104, threshold setting unit 1c sets real threshold Vt based on that frequency information). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the photodetection device of Yeh in view of Ichiyanagi with the additional teachings of Ichiyanagi with a reasonable expectation of success in order to provide feedback for set the threshold according to detected noise, ensuring only reflected light signals exceed the final threshold, thereby improving measurement accuracy and detector performance (Ichiyanagi ¶¶ 98, 100-104).
Allowable Subject Matter
Claim 12 is 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. Claims 8 and 14-20 would be allowable if rewritten to overcome the rejection under 35 U.S.C. 112(b) set forth in this Office action and to include all limitations of the base claim and any intervening claims. A statement of reasons for the indication of allowable subject matter are as follows.
With respect to claim 8, Yeh in view of Ichiyanagi does not teach the photodetection device of claim 7, wherein the firing detection circuit outputs a signal according to a comparison result between a signal of the one end of the photodetection element and the threshold, the monitor circuit includes an oscillator that outputs an oscillation signal having a frequency according to an output signal of the firing detection circuit, and a frequency counter that detects a frequency of the oscillation signal, and the threshold control circuit controls the threshold based on a count value of the frequency counter. Neither Dubey, Bodlovic, Tsukuda2, Guo nor Tsukuda remedies the deficiencies of Yeh in view of Ichiyanagi.
With respect to claim 12, Tsukuda in view of Dubey does not teach the photodetection device of claim 10, wherein the threshold control circuit sets the threshold to a minimum value of a control range of the threshold in which a variation amount of the occurrence rate of the pulse signal falls within the predetermined amount. Neither Bodlovic, Tsukuda2, Guo, Yeh nor Ichiyanagi remedies the deficiencies of Tsukuda in view of Dubey.
With respect to claim 14, neither Tsukuda nor Yeh in view of Ichiyanagi teach the photodetection device of claim 1, further comprising a photodetection element group including a plurality of the photodetection elements arranged in a predetermined direction; and a selection circuit that selects any of the photodetection elements in the photodetection element group, wherein the firing detection circuit, the monitor circuit, and the threshold control circuit are provided corresponding to the photodetection element group, the monitor circuit monitors an output signal of the firing detection circuit corresponding to the photodetection elements selected by the selection circuit among the corresponding photodetection element groups, and the threshold control circuit controls the threshold of the firing detection circuit corresponding to the photodetection elements selected by the selection circuit based on the monitor output of the monitor circuit. Neither Bodlovic, Tsukuda2, Guo, nor Dubey remedies the deficiencies of Tsukuda and Yeh in view of Ichiyanagi.
The remaining prior art made of record and not relied upon is considered pertinent to applicant’s disclosure, as noted in the attached PTO 892, include:
Chen (US 20220120872 A1) discloses the comparison of SiPM pulses with an adjustable threshold, counts qualifying pulses, and dynamically adjusts thresholds based on incident or background light intensity, individually or collectively across receivers. However, Chen does not teach the oscillator/frequency counter of claim 8, the minimum value selection within a stable pulse rate range of claim 12, nor the selection circuit and group shared detection, monitoring, and threshold control architecture of claim 14.
Zhu (US 20230061653 A1) discloses a SPAD, comparator-based firing detection, output waveform monitoring, adaptive threshold control, and multi-pixel arrangements. However, Zhu does not teach the oscillator/frequency counter feedback of claim 8, the minimum value selection within a stable occurrence rate range of claim 12, nor the group-based element selection architecture of claim 14.
In sum, the prior art made of record teach or suggest various aspects of the invention, but none in a way that would fully anticipate or render obvious all limitations as specifically recited in claims 8, 12 and 14. Accordingly, claim 12 would be allowable if rewritten in independent form, including all limitations of its base claim and any intervening claims. Claims 8 and 14 would be allowable if rewritten to overcome the rejection under 35 U.S.C. 112(b) set forth in this Office action and to include all limitations of the base claim and any intervening claims. Claims 15-20 would be allowable for the same reason as claim 14 by virtue of dependency.
Conclusion
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1 Dubey, P.K., Jain, S.L., Arya, B.C. et al. Discriminator threshold selection logic to improve signal to noise ratio in photon counting. MAPAN 25, 63–70 (2010).
Prosecution Insights