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 .
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 2 and 10 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.
Regarding claim 2, the claim recites the limitation that the output of the digital filter “is generated to minimize the analog error signal” however it is not clear what is meant by this limitation. It appears from the specification that the digital filter minimizes the analog error signal and outputs it and not that the output itself does the minimizing.
Regarding claim 10, the claim refers to a “high voltage drive,” however the term “high voltage” is relative and there is no indication as to what would constitute “high” versus low. Therefore, it is unclear what would satisfy the limitation of high.
All claims which depend from those above are rejected for the same reasons due to their dependency thereon.
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.
Claim(s) 1-5, 7-10 and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ward US 5,481,914 and Malvern et al. US 2016/0252544.
Regarding claim 1, Ward discloses a micromechanical gyroscope (abstract) comprising a suspended spring-mass system (suspended proof mass, column 5, line 12) comprising a driven mass 64,
a drive system (drive electrode 86) operatively coupled the driven mass to impart a drive motion onto the driven mass based on a drive signal 78;
one or more drive sense electrodes 68, 70 located proximate to the driven mass to generate a drive sense signal based on the drive motion of the driven mass (in plane sense electrode 68 generates a drive sense signal 72 for the driven mass in the plane in which it’s driven); and
processing circuitry 50 configured to receive the drive sense signal 72, rectify the drive sense signal (via comparator 97 and integrating amplifier 98, column 9 lines 14-37), subtract the rectified drive sense signal from a drive reference signal to generate an analog error signal (comparator 98 compares the rectified signal to a reference),
and generate the drive signal 78 in proportion to the drive control signal (the signal outputted by multiplier 106 would be in proportion to the input signal. Therefore, Ward differs from the claimed invention in that it does not explicitly digitize the analog error signal to generate a digitized error signal, digitally filter the digitized error signal with a digital filter, generate a pulse-width-modulated drive control signal based on the digitally filtered digitized error signal as claimed.
Malvern teaches a mems accelerometer comprising a suspended spring-mass system (paragraph 0020) which includes drive sense electrodes (fig. 2) and a drive control signal 30a, 30b which is adjusted for error. Paragraph 0013 teaches generating a pulse-width-modulated (PWM) drive signal and an error signal. The output from the accelerometer is originally analog and can be converted to digital (paragraph 0022) which would then be used for determination of the error in a digital form prior to being fed back as the drive signal (paragraph 0025 for example discloses the PWM drive signals). Malvern further discloses a digital filter in the form of loop filter 24 through which the error signal would be filtered. It would have been obvious to one of ordinary skill in the art at the time of filing to have combined the teachings of Malvern with those of Ward in order to provide a similar error correction for a drive signal using a PWM drive signal to optimize open loop gain and increase precision of the sensor.
Regarding claims 2-4, the digital filter 24 of Malvern is configured such that the output minimizes the analog error signal (by correcting for it), applies a proportional-integral control function to the signal (paragraph 0028) and applies a sine function to the signal (paragraph 0044).
Regarding claim 5, paragraph 0052 of Malvern discloses using a low-pass filter 126 applied to the output of the device. It would have been obvious to one of ordinary skill in the art at the time of filing to have combined the low-pass filtering means of Malvern with the device of Ward in order to create a final output signal which is free from modulation, thereby improving the accuracy of the sensor.
Regarding claim 7, Ward teaches a subtraction circuit configured to subtract the drive sense signal from the drive reference signal to generate an analog error signal (integrating amplifier 98 compares the signal to a reference and detects a difference) and a drive circuit to generate the drive signal in proportion to a control signal (at drive electrode 86). In combination with Malvern, the drive signal is in proportion to the pulse-width-modulated drive control signal as indicated above.
Regarding claim 8, Ward teaches a reference signal input Vref which when combined with the rectified signal would remove a portion of the drive sense signal that corresponds to the drive reference signal to generate the error signal, and integrator 98 coupled to the reference signal input to integrate the error signal over a period of the drive signal to generate the error signal (column 9 lines 14-37).
Regarding claim 9, Ward teaches a demodulator configured to receive the drive signal 76 to generate a demodulated signal based on the frequency of the drive signal as claimed which would comprise the demodulated drive signal (column 10 lines 47-61).
Regarding claim 10, the drive signal of Ward would include a high voltage drive configured to modify an amplitude of the drive signal (column 3, lines 53-67). In combination with Malvern as above, the signal would be the pulse-width-modulated signal and therefore in proportion to it.
Regarding claim 16, the masses of Ward and Malvern are proof masses as claimed.
Claim(s) 12-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ward and Malvern as applied to claim 1 above, and further in view of Collin et al. US 2017/0328712.
Regarding claim 12, Ward and Malvern disclose the claimed invention but do not explicitly teach the drive start circuit as claimed. Collin discloses a controller for a MEMS gyroscope which provides a startup signal at the beginning of operation (paragraph 0035). It would have been obvious to one of ordinary skill in the art at the time of filing to have combined the teachings of Collin with those of Ward and Malvern in order to provide a similar startup signal in order to place the mass into motion initially for sensing.
Regarding claim 13, the startup signal of Collin is a burst signal as claimed (paragraph 0035 discloses the signal as a pulse).
Regarding claims 14-15, the claims are directed towards specific values of the drive signal which would be capable of being generated by the combination of Ward, Malvern and Collin and it has been held that a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus satisfying the claimed structural limitations. Ex parte Masham, 2 USPQ2d 1647 (1987), therefore the device in the combination meets all of the limitations claimed.
Claim(s) 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ward and Malvern as applied to claim 1 above, and further in view of Hsu et al. US 2012/0160027.
Regarding claim 17, Ward and Malvern discloses the claimed invention including a driven proof mass, but do not explicitly teach the driven mass coupled to a proof mass to impart the drive motion on the proof mass as claimed. Hsu teaches a gyroscope in which a driven mass (frame 13) is driven to impart motion onto a proof mass 11 (paragraph 0011). Iti would have been obvious to one of ordinary skill in the art at the time of filing to have combined the teachings of Hsu with those of Ward and Malvern in order to provide a driving frame structure to better isolate the proof mass and increase its sensitivity.
Allowable Subject Matter
Claims 6 and 11 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: with regard to claim 6, the prior art cited above fails to teach the digital filter configured to linearize a transfer function of a pulse width modulator that generates the pulse-width-modulated drive control by applying a pre-distortion function to the output of the digital filter as claimed.
With regard to claim 11, the prior art fails to teach the specifics of the comparator and the phase locked loop reference which is applied to the analog and digital processing circuitry in the claimed manner.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Mark A. Shabman whose telephone number is (571)272-8589. The examiner can normally be reached M-F 8:00-4:30 EST.
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/MARK A SHABMAN/ Primary Examiner, Art Unit 2855