Non-Final Rejection
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . This application was filed with claims 1-47, which are pending.
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 17-21, 25, 36 and 40 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.
Claims 17-21, 36, and 40 each use “the active medium” but there is insufficient antecedent basis for this term. The claims should use “the gain medium” for appropriate antecedent basis.
Claim 20 states the active medium is “erbium-ytterbium-doped yttrium aluminum garnet (Er:YAG).” These are inconsistent and thus unclear which is meant. Claim 21 already used Er,Yb:YAG so it is believed claim 20 should just be erbium-doped.
Claim 25 recites “the one or more laser diodes” but there is insufficient antecedent basis for this term. It is believed it should depend from claim 24.
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 1-7, 9-16, 26-28, 44-45, and 47 are rejected under 35 U.S.C. 103 as being unpatentable over JP 2012-142523 A (“JP ‘523”).
Regarding claim 1, JP ‘523 describes in Fig. 1 starting at [0014] a passive Q-switched synchronous laser system comprising:
a. an optical cavity having an optical axis; (dashed line between 103a and 106a)
b. a gain medium 103 disposed in the optical cavity along the optical axis.
c. pump means 102 configured to supply the gain medium with pump energy.
d. a passive Q-switch 105 disposed in the optical cavity along the optical axis, wherein the passive Q-switch switches the Q factor of the optical cavity from a low state to a high state, and wherein the optical cavity produces laser output pulses as a result of the passive Q-switch switching the Q state of the optical cavity. See [0020], and the wherein clauses are just the definition of a Q-switch.
e. a photodetector 108 configured to detect the laser output pulses and to produce corresponding signals indicative of and synchronous with the laser output pulses. While this is only called a “pulse timing monitor” and no further information is given, it takes a light input signal and outputs a signal indicative of that light input signal, which a person of ordinary skill would understand is very likely a photodetector. To the extent it is not inherently a photodetector, the examiner takes Official Notice that photodetectors are well known in the art to detect laser outputs and provide an electrical signal representative of the output. It would have been obvious to use a photodetector as a simple substitution of one known element for another to yield predictable results. See MPEP 2143 I.B. The claim differs from JP ‘523 in using a “pulse timing monitor” which is perhaps not a photodetector, but photodetectors are of course well known and can do the same exact thing of detecting a light input signal and outputting an electrical signal based on the light input. A person of ordinary skill could have used a photodetector and that substitution would have been predictable because this is exactly what a photodetector is meant to and capable of doing.
f. control circuitry 110-112 configured to receive the signals from the photodetector and control application of power to the pump means to synchronize the output laser pulses to a reference clock signal CS from 109. [0025]-[0028].
Regarding claim 2, the purpose of a Q switched laser is to provide a pulsed output, and JP ‘523 Fig. 2 shows the laser pulse output is a train of pulses having some repetition frequency. See Fig. 2, LO.
Regarding claim 3, the whole system from 107 to 102 is a feedback loop including the control circuitry comprises a feedback loop with an error signal based on the frequency and phase difference between the output pulse train and the reference clock signal. Note the comparator 110 provides signals based on frequency and phase difference. [0029]-[0038].
Regarding claims 4-7, the JP ‘523 passive Q-switch comprises a saturable absorber and may be Cr4+:YAG, Co:spinel, or V3+:YAG. [0023].
Regarding claim 9, in JP ‘523 the gain medium comprises a crystal or glass matrix doped with rare earth ions. [0023]
Regarding claim 10-14, the laser wavelength may be in the 1.0 micron band or the 1.5-1.7 micron bad, overlapping with the claimed ranges. [0023]-[0024]. Generally, when the claim overlaps or lies within a range disclosed in the prior art a prima facie case of obviousness. See MPEP 2144.05 I.
Regarding 15, JP ‘523 does not specifically disclose the output is 1522 nm, but this is considered within the 1.5-1.7 micron band as discussed above re: claims 10-14, and therefore is prima facie obvious.
Regarding 16, JP ‘523 does not specifically disclose the output is 1064 nm, but this is considered within the 1.0 micron band as discussed above re: claims 10-14, and therefore is prima facie obvious. Additionally, this wavelength is not critical or unexpected as it is widely known as the primary emission from Nd:YAG, which JP ‘523 does disclose at [0023].
Regarding claim 26, power supplies 111,112 will determine the frequency, phase, duty cycle, and DC value of the pump drive current based on their outputs. These output control signals can therefore be considered “characterized” by these things.
Regarding claim 27, power supplies 111,112 will drive the pump 102. 111 supplies pulses and can be considered to provide switching that modulates the pump drive. To the extent applicant means more than this, such as a switched mode power supply, the examiner takes Official Notice that such power supplies are well known and it would have been obvious to a person of ordinary skill in the art to use them as they are generally very efficient. Furthermore, clear enablement of this power supply is not found in the specification so it must be a well-known thing.
Regarding claim 28, power supplies 111,112 will determine the frequency, phase, duty cycle, and DC value of the pump drive current based on their outputs. 111 supplies pulses and can be considered modulated.
Regarding claim 44, the claim is a method of controlling a Q-switched laser, the method comprising “providing” and “using” the elements of claims 1-2, and the claim is therefore rejected for the same reasons.
Regarding claim 45, the claim is a method providing the control circuitry of claim 3, and the claim is therefore rejected for the same reasons.
Regarding claim 47, the control signals indicate the PRF given that is compared to the clock.
Claims 8, 15, 17-25, 29-43, and 46 are rejected under 35 U.S.C. 103 as being unpatentable over JP ‘523 in view of US 9,810,786 to Welford et al. (“Welford”)
Regarding claim 8, JP ‘523 does not describe that there is an OPO as claimed. Welford teaches in Figs. 13-17, discussion starting at col. 32 line 53, that a passive Q-switched laser can pump an OPO similarly to that claimed. It would have been obvious to a person of ordinary skill in the art to use an OPO because OPO’s allow the output to be broadly tunable over a wide range and thus usable for many different applications.
Regarding 15, JP ‘523 does not specifically disclose the output is 1522 nm, but again this is considered within the 1.5-1.7 micron band as discussed above re: claims 10-14 and therefore is prima facie obvious. Additionally, this is known as a typical output wavelength of Er,Yb:YAB, which is shown in Welford. See rejection of claim 17 below.
Regarding claims 17 and 21, JP ‘523 does not use Er,Yb:YAB or Er,Yb:YAG. These are known gain medium crystals. Welford shows Er,Yb:YAB is known. Col. 23 line 41. The examiner takes Official Notice that Er,Yb:YAG is also known in the art. It would have been obvious to a person of ordinary skill in the art to use different gain mediums because the skilled artisan knows that different crystals provide different outputs, and they would choose any known crystal as needed for their particular application.
Regarding claims 18-20, the JP ‘523 gain medium can be Nd:YVO4, Nd:YAG, or Er:YAG. [0023]-[0024].
Regarding claims 22-23, JP ‘523 does not show the PRF of the pulses is about 10 kHz to about 500 kHz or about 200 kHz to about 500 kHz. Welford shows that it was known for passive Q-switched lasers to have such repetition rates. Col. 21 line 56 to col. 22 line 59. It would have been obvious to a person of ordinary skill in the art that the requisite repetition rate depends on the particular application, therefore a person of ordinary skill would use lasers having such repetition rates as needed for their particular application.
Regarding claims 24-25, JP ‘523 does not say what the pump source 102 is. It is typical for rare earth doped crystals such as those in JP ‘523 to be pumped by laser diodes, and certain crystals may best be pumped at 970-980 nm, depending on the absorption characteristics of the crystal. See Welford, col. 24 lines 57 to col. 25 line 11, showing a passive Q-switched laser being pumped by laser diodes at, among other wavelengths, 976 or 980 nm. It would have been obvious to a person of ordinary skill in the art to use laser diodes at such wavelengths as a simple substitution of one known element for another to yield predictable results. MPEP 2143 I.B. JP ‘523 shows the bulk of the claim but gives no details of the pump source. Such a source was known as in Welford. A person of ordinary skill could use such pumps and the result would have been predictable because JP ‘523 already has a pump, this is just choosing the specific one, and the skilled artisan knows how to choose a pump based on the gain medium being used. A person of ordinary skill would likewise select the appropriate pump wavelength to achieve lasing for whatever particular crystal is chosen.
Regarding claim 29:
29. An illumination system for scanned lidar, the system comprising:
JP ‘523 describes an illumination system, but does not say it is for lidar. This is found in Welford and is discussed in the limitations b.-c. below.
a. a laser system operative to produce a laser output, the laser system comprising;
i. an optical cavity having an optical axis;
ii. a gain medium disposed in the optical cavity along the optical axis;
iii. pump means configured to supply the gain medium with pump energy;
iv. a passive Q-switch disposed in the optical cavity, wherein the passive Q-switch is configured to absorb optical energy received from the gain medium up to a threshold and then to transmit the optical energy once the threshold has been exceeded, wherein the passive Q-switch switches the Q factor of the optical cavity from a low state to a high state, and wherein the optical cavity produces laser output pulses as a result of the passive Q-switch switching the Q state of the optical cavity;
v. a photodetector configured to detect the laser output pulses and to produce corresponding signals indicative of and synchronous with the laser output pulses; and
vi. control circuitry configured to receive the signals from the photodetector and control application of power to the pump means to synchronize the output laser pulses to a reference clock signal;
The laser system is the same as claim 1, except additionally requires the Q switch configured to absorb optical energy received from the gain medium up to a threshold and then to transmit the optical energy once the threshold has been exceeded. This is describing the operation of a saturable absorber Q switch, which is the subject of dependent claim 4. Claims 1 and 4 are taught as above, and thus limitation a. here is taught for the same reasons.
b. an optic operative to receive the laser output pulses and produce a beam output having an angular spread in a first direction; and
c. a scanning system operative to scan the beam output across a desired angular span in a direction substantially orthogonal to the first direction.
Welford describes passive Q switched lasers, such as those found in JP ‘523, may be used as a light source in lidar systems. See col. 21-22 discussing varying examples of the light source. Welford also describes that a lidar system may include an optic that receives laser pulses and produces beams having a spread in the first direction, and a scanning system that scans the beam across a desired span orthogonal to the first direction. Col. 19 line 62 – col. 20 line 18. It would have been obvious to a person of ordinary skill in the art to use the JP ‘523 laser in a lidar system because Welford already uses similar passive Q switched lasers and lidar is a useful known application for lasers. The JP ‘523 laser in particular being useful in that the pulse output timing can be controlled and made steady due to synching with the reference clock.
Alternatively, Welford may be primary reference, and includes limitations b and c. Welford further describes a diode pumped passive Q switched laser, see Fig. 10 and discussion, and thus clearly has i.-iii. of limitation a. with cavity, gain medium 410, saturable absorber Q switch 420, and pump 430, but not limitations v.-vi. These are found in JP ‘523 as in the rejection of claim 1. It would have been obvious to a person of ordinary skill in the art to add these features so that the laser can be synched to a reference clock so that the pulse output timing can be controlled, as taught by JP ‘523.
Regarding claims 30-41, see rejection of claims 2-7, 9-10, 12, 14, 17, 22 above.
Regarding claims 42-43, as above it would have been obvious to use Welford’s scanning system. Welford additionally teaches that such scanning may be point scans or line scans as claimed. Col. 6 lines 63-64 (scanning results in point clouds); col. 8 lines 14-16 (scanning to map distance to points in the field of regard); col. 14 lines 38-65 (scanning along straight lines).
Regarding claim 46, see rejection of claim 22 above.
Conclusion
Other pertinent art is cited.
DE 10 2019 212 608 A1 also shows a passive Q switched laser for LIDAR that is operated with a clock. The system is fixed to the clock and therefore would be considered in synch. [0024].
US 2003/0058904 suggests synching a Q switched laser to a reference clock. [0083], [0114].
US 2003/0160034 suggests synching a Q switched laser to a reference clock. [0144].
US 2022/0209489 cites JP ‘523 in the specification and improves on it.
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/JAMES A MENEFEE/ Primary Examiner, Art Unit 2828