CN102192707A - Physical quantity transducer and physical quantity measuring method - Google Patents

Physical quantity transducer and physical quantity measuring method Download PDF

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CN102192707A
CN102192707A CN2010101314864A CN201010131486A CN102192707A CN 102192707 A CN102192707 A CN 102192707A CN 2010101314864 A CN2010101314864 A CN 2010101314864A CN 201010131486 A CN201010131486 A CN 201010131486A CN 102192707 A CN102192707 A CN 102192707A
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cycle
interference waveform
oscillation
instrumentation
period
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CN102192707B (en
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上野达也
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Azbil Corp
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Azbil Corp
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Abstract

The invention discloses a physical quantity transducer, which is used for measuring the displacement and the speed of an object by high resolution capability so as to shorten the required time of measurement. The physical quantity transducer comprises a semiconductor laser (1), a laser driver (4), a photodiode (2), a current-voltage transformation amplifying part (5), a signal extraction part (7) and a calculation part (8), wherein the semiconductor laser (1) emits laser to a measured object (10), and the laser driver (4) is used for driving the semiconductor laser (1) to actuate so that at least one of a first oscillation period in which an oscillation wavelength is continuously and monotonously increased and a second oscillation period in which the oscillation wavelength is continuously and monotonously reduced reoccurs; the photodiode (2) and the current-voltage transformation amplifying part (5) are used for detecting electrical signals which comprise interference waveforms, and the interference waveforms are generated by the self-mixing effect of the laser emitted by the semiconductor laser (1) and returned light of the object (10); the signal extraction part (7) is used for measuring the cycle of the interference waveforms contained in the output signals of the current-voltage transformation amplifying part (5); and the calculation part (8) is used for correcting a measuring result by comparing the measuring result of the signal extraction part (7) with a reference cycle, and calculating at least one of the displacement and the speed of the object (10) according to the corrected cycles.

Description

Physical quantity transducer and physical quantity measuring method
Technical field
The present invention relates to physical quantity transducer and physical quantity measuring method, this physical quantity transducer is according to the laser of semiconductor laser radiation and the information of the interference of the self-mixing effect generation of the back light of object, the displacement of instrumentation object, speed.
Background technology
FMCW (Frequency Modulated Continuous Wave) radar and standing wave radar, carry out in displacement (speed) method for measuring from the employing principle of interference of mixed type laser sensor etc., based on the displacement of the frequency computation part determination object of beat frequency and interference fringe and speed the time, generally adopt the signal Processing of FFT (Fast Fourier Transform) etc. or the counting of interference fringe to handle.But exist such problem, in order to realize high resolution capacity by FFT, therefore the data of sample time that need be very long and higher sample period need very many processing times.Again, in the counting of interference fringe is handled, in order to measure displacement less than half-wavelength, need make sensor carry out physical vibration, or the amplitude of interference fringe resolved, so then exist can only instrumentation as the problem of the vibration of the periodic motion of determination object and, the counting of interference fringe handles time-consuming problem.
On the one hand, the inventor has proposed to utilize the laser instrumentation device (with reference to patent documentation 1) of wavelength-modulated type of the self-mixing effect of semiconductor laser.The structure of this laser instrumentation device as shown in figure 20.The laser instrumentation utensil of Figure 20 has: to the semiconductor laser 201 of object 210 lases; With the light output transform of semiconductor laser 201 is the photodiode 202 of electric signal; Lens 203, these lens carry out light harvesting and this illumination is mapped to object 210 to the light from semiconductor laser 201, simultaneously the back light of object 210 are carried out laser and make it incide semiconductor laser 201; Make semiconductor laser 201 during first vibration that oscillation wavelength increases continuously and the laser driver 204 of second duration of oscillation alternate repetition that reduces continuously of vibration wavelength; The output current of photodiode 202 is transformed to voltage and amplified current-voltage transformation amplifier 205; Signal extracting circuit 206 with the output voltage second differential of current-voltage conversion amplifier 205; The counting circuit 207 that the number of the MHP that comprises in the output voltage to signal extracting circuit 206 is counted; The calculation element 208 of the distance of calculating and object 210 and the speed of object 210; The display device 209 that shows the result of calculation of calculation element 208.
Laser driver 204 will offer semiconductor laser 201 with the triangular wave drive current that the rate of change with regulation increases and decreases repeatedly as injection current along with the time.Thus, noise spectra of semiconductor lasers 201 drives, make during first vibration that oscillation wavelength increases continuously with the rate of change of regulation and second vibration that oscillation wavelength reduces continuously with the rate of change of regulation during alternate repetition.Figure 21 is the synoptic diagram that changes the time of the oscillation wavelength of demonstration semiconductor laser 201.Among Figure 21, P1 was first duration of oscillation, and P2 was second duration of oscillation, and λ a is triangle wave period for minimum value, the λ b of oscillation wavelength during each for maximal value, the Tt of oscillation wavelength during each.
By lens 203 light harvestings, incide object 210 from semiconductor laser 201 emitting lasers.Light scioptics 203 light harvestings by object 210 reflections incide semiconductor laser 201.Photodiode 202 is an electric current with the light output transform of semiconductor laser 201.Current-voltage conversion amplifier 205 is transformed to voltage and amplification with the output current of photodiode 202, and the output voltage of 206 pairs of current-voltage conversion of signal extracting circuit amplifier 205 carries out second differential.Counting circuit 207 is counted the number of the mould jump pulse (MHP) in the output voltage that is included in signal extracting circuit 206 respectively at first duration of oscillation P1 and second duration of oscillation P2.Calculation element 208 calculates and the distance of object 210 and the speed of object 210 according to minimum oscillation wavelength lambda a, the full swing wavelength X b of semiconductor laser 201, the number of MHP among first duration of oscillation P1 and the number of the MHP among second duration of oscillation P2.According to such laser instrumentation device from mixed type, can carry out the displacement instrumentation of resolution characteristic of half-wavelength degree of semiconductor laser 201 and the resolution characteristic that is inversely proportional to the wavelength-modulated amount of semiconductor laser 201 apart from instrumentation.
Patent documentation 1 TOHKEMY 2006-313080 communique
Summary of the invention
Invent problem to be solved
According to from mating type laser instrumentation device, with fmcw radar and standing wave radar, compare in the past from mixed type laser sensor etc., can be with the displacement and the speed of high resolution capacity instrumentation determination object.But, from mating type laser instrumentation device since the same its displacement calculating with FFT and the speed needs instrumentation time to a certain degree (in the example of patent documentation 1, be meant semiperiod of carrier wave of the oscillation wavelength modulation of semiconductor laser), therefore exist the problem that in the instrumentation of the fast determination object of velocity variations, produces the instrumentation error.Therefore owing to need the number of MHP is counted in the signal Processing, also exist the problem that is difficult to realize semiconductor laser less than the resolution characteristic of half-wavelength again.
The present invention is in order to solve above-mentioned problem, aim to provide a kind of can be with the displacement and the speed of high resolution characteristic instrumentation object, and can shorten physical quantity transducer and the physical quantity measuring method of required time of instrumentation.
The means of dealing with problems
The invention provides a kind of physical quantity transducer, comprising: to the semiconductor laser of determination object emission laser; The oscillation wavelength modulating unit starts the action of described semiconductor laser, makes during dull continuously first vibration that increases of oscillation wavelength and at least a in dull continuously second duration of oscillation that reduces of vibration wavelength occurs repeatedly; Detecting unit, its detection comprises the electric signal of interference waveform, and described interference waveform is produced by the self-mixing effect from the back light of described semiconductor laser emitted laser and described determination object; Signal extraction unit, it carries out instrumentation to the cycle of the described interference waveform in the output signal that is included in this detecting unit when the described interference waveform of each input; The cycle correction unit, it is revised described instrumentation result by the instrumentation result of this signal extraction unit and reference period are compared; Computing unit, it calculates the displacement of described determination object and at least one item in the speed based on by revised each cycle of this cycle correction unit.
Again, in a configuration example of physical quantity transducer of the present invention, described computing unit, according to the mean wavelength of the frequency of the sampling clock in cycle of the described interference waveform of instrumentation, described reference period, described semiconductor laser, by the variable quantity of revised cycle of described cycle correction unit, calculate at least one in the displacement of described determination object and the speed with respect to described reference period.
Again, in a configuration example of physical quantity transducer of the present invention, described cycle correction unit, by described signal extraction unit instrumentation to cycle of interference waveform during less than stated number k times of described reference period, wherein k be less than 1 on the occasion of, then with the cycle of this interference waveform with the waveform that combined cycle is obtained is as a waveform as the cycle of revised interference waveform the cycle of the cycle of the interference waveform that obtains of institute's instrumentation after merging afterwards; By described signal extraction unit instrumentation to cycle of interference waveform be described reference period (m-k) doubly more than and during less than (m+k) of described reference period times, wherein m is the natural number more than 2, the cycle that obtains behind the branches such as period m with this interference waveform, the waveform in revised cycle had m respectively as the revised cycle.
Again, in a configuration example of physical quantity transducer of the present invention, described stated number k is 0.5.
Again, in a configuration example of physical quantity transducer of the present invention, described cycle correction unit, the cycle of the described interference waveform with described determination object when static or described be about to revise before the mean value in cycle of interference waveform of the stated number that arrives of institute's instrumentation as described reference period.
Again, in a configuration example of physical quantity transducer of the present invention, also comprise: counting unit, it is counted respectively in described first duration of oscillation and described second duration of oscillation the number of the described interference waveform in the output signal that is included in described detecting unit; Metrics calculation unit, its according to by this counting unit to the number of interference waveform count during the count results of minimum oscillation wavelength, full swing wavelength and described counting unit calculate and described determination object between distance; The computation of Period unit, it tries to achieve cycle of described interference waveform according to the distance that this metrics calculation unit calculated, described cycle correction unit, the cycle that described computation of Period unit is tried to achieve is as described reference period.
Again, in a configuration example of physical quantity transducer of the present invention, also comprise: counting unit, it is counted respectively in described first duration of oscillation and described second duration of oscillation the number of the described interference waveform in the output signal that is included in described detecting unit; Distance proportion number computing unit, the mean value of its number by calculating described interference waveform, the number of trying to achieve with the proportional interference waveform of mean distance of described semiconductor laser and described determination object is the distance proportion number; The computation of Period unit, in the cycle that it calculates described interference waveform according to described distance proportion number, the cycle that described computation of Period unit is tried to achieve in described cycle correction unit is as described reference period.
The invention provides a kind of physical quantity measuring method, comprising: the vibration step, start described semiconductor laser, make oscillation wavelength first duration of oscillation and at least a repeatedly appearance of vibration wavelength in dull continuously second duration of oscillation that reduces of dullness increase continuously; Detect step, detect the electric signal that comprises interference waveform, described interference waveform is produced by the self-mixing effect from the back light of described semiconductor laser emitted laser and determination object; The signal extraction step is carried out instrumentation to the cycle that is contained in the described interference waveform in the output signal that described detection step obtains at every turn when importing interference waveform; The cycle correction step compares by instrumentation result and reference period with this signal extraction step, and described instrumentation result is revised; Calculation procedure based on revised each cycle of this cycle correction step, calculates the displacement of described determination object and at least one item in the speed.
The invention effect
According to the present invention, calculate by cycle based on each interference waveform, can be with displacement and speed than high in the past resolution characteristic determination object.Again, than in the past in mixed type laser instrumentation device, need expend the instrumentation time of the semiperiod of carrier wave, in the present invention, owing to can try to achieve the displacement and the speed of determination object according to the cycle of each interference waveform, therefore shortened the needed time of instrumentation significantly, and can be corresponding with the fast determination object of velocity variations.Further, in the present invention, compare, can revise the circular error of interference waveform, therefore can improve the instrumentation precision of displacement and speed by instrumentation result and reference period with signal extraction unit.
Description of drawings
Fig. 1 is the block diagram of the structure of the physical quantity transducer that shows that first embodiment of the present invention relates to.
Fig. 2 is the oscillogram that schematically shows the output voltage waveforms of the output voltage waveforms of the current-voltage conversion enlarging section that first embodiment of the invention relates to and filtering portion.
Fig. 3 is the figure that is used to illustrate the mould jump pulse.
Fig. 4 is the figure of relation that shows the output waveform of the oscillation wavelength of semiconductor laser and photodiode.
Fig. 5 is the block diagram of configuration example that shows the signal extraction portion of first embodiment of the present invention.
Fig. 6 is the figure of action that is used to illustrate the signal extraction portion of first embodiment of the invention.
Fig. 7 is the block diagram of configuration example that shows the calculating part of first embodiment of the present invention.
Fig. 8 is the figure of action that is used to illustrate the cycle correction portion of first embodiment of the present invention.
Fig. 9 is instrumentation result's the figure of correction principle that is used to illustrate the signal extraction portion of first embodiment of the present invention.
Figure 10 is the figure that the number of degrees in the cycle of demonstration mould jump pulse distribute.
Figure 11 is the figure that shows the number of degrees distribution that becomes the twice modulus of periodicity jump pulse cycle.
Figure 12 is the figure that is distributed by the number of degrees in the cycle of the mould jump pulse of two five equilibriums in the mould jump pulse that is short of when showing counting.
Figure 13 is the figure that is distributed by the number of degrees in the cycle of the mould jump pulse of two five equilibriums in the mould jump pulse that is short of when showing counting.
Figure 14 is the block diagram that shows the configuration example of the calculating part in second embodiment of the present invention.
Figure 15 is the block diagram that shows the configuration example of the calculating part in the 3rd embodiment of the present invention.
Figure 16 is the figure of the example that shows that time of the count results of the count section in the 3rd embodiment of the present invention changes.
Figure 17 is the figure of other examples of showing that time of the count results of the count section in the third embodiment of the invention changes.
Figure 18 is the figure of other examples of showing that time of the oscillation wavelength of the semiconductor laser in the 4th embodiment of the present invention changes.
Figure 19 is the block diagram of the formation of the physical quantity transducer that shows that fifth embodiment of the invention relates to.
Figure 20 is the block diagram that shows the formation of existing laser instrumentation device.
Figure 21 is the figure of 1 example showing that time of the oscillation wavelength of the semiconductor laser in the laser instrumentation device of Figure 20 changes.
Embodiment
First embodiment
Below with reference to accompanying drawing embodiments of the present invention are described.Fig. 1 is the block diagram of the structure of the physical quantity transducer that shows that first embodiment of the invention relates to.
The physical quantity transducer of Fig. 1 has: to launch the semiconductor laser 1 of laser as the object 10 of determination object; With the light output transform of semiconductor laser 1 is the photodiode 2 of electric signal; Lens 3, the light that these lens 3 noise spectra of semiconductor lasers 1 are sent carry out light harvesting and emission, and the back light to object 10 carries out light harvesting and makes this back light incide semiconductor laser 1 simultaneously; Drive the laser driver 4 as the oscillation wavelength modulating unit of semiconductor laser 1; The output current of photodiode 2 is transformed to voltage and amplified current-voltage transformation enlarging section 5; From the output voltage of current-voltage conversion enlarging section 5, remove the filtering portion 6 of carrier wave; Conduct in the output voltage that is included in filtering portion 6 is carried out the signal extraction portion 7 of instrumentation from the cycle of the mould jump pulse of mixed signal (below be called MHP); The displacement of each the computation of Period object 10 that arrives based on signal extraction portion 7 instrumentations and the calculating part 8 of speed; The display part 9 that shows the result of calculation of calculating part 8.
Photodiode 2 and current-voltage conversion enlarging section 5 constitute detecting unit.Below for convenience of explanation, suppose that semiconductor laser 1 adopts the type (VCSEL type, DFB laser class) that does not have mould jumping phenomenon.
Laser driver 4 will increase and decrease the triangular wave drive current repeatedly with certain rate of change and offer semiconductor laser 1 as injection current along with the time.Like this, semiconductor laser 1 is driven to, and with the injection current size oscillation wavelength is alternately repeated with second duration of oscillation P2 that certain rate of change reduces continuously with first duration of oscillation P1 and the oscillation wavelength that certain rate of change increases continuously.At this moment, the time of the oscillation wavelength of semiconductor laser 1 changes as shown in figure 21.In the present embodiment, the pace of change of the oscillation wavelength of semiconductor laser 1 must be certain.
From semiconductor laser 1 emitting laser scioptics, 3 light harvestings and incide object 10.Light scioptics 3 light harvestings by object 10 reflections incide semiconductor laser 1.But neither carry out light harvesting by scioptics 3.Photodiode 2 is arranged near the inside of semiconductor laser 1 or its, is electric current with the light output transform of semiconductor laser 1.Current-voltage conversion enlarging section 5 is transformed to voltage and amplification with the output current of photodiode 2.
Filtering portion 6 has the function that extracts overlapped signal from modulating wave.Fig. 2 (A) schematically shows the output voltage waveforms of current-voltage conversion enlarging section 5, and Fig. 2 (B) schematically shows the output voltage waveforms of filtering portion 6.These figure have shown from the waveform of Fig. 2 of the output that is equivalent to photodiode 2 (A) (modulating wave), remove the waveform (carrier wave) of semiconductor laser 1 of Fig. 2 after, extract the process of the MHP waveform (interference waveform) shown in Fig. 2 (B).
Then, signal extraction portion 7 instrumentation when each MHP takes place is included in the cycle of the MHP in the output voltage of filtering portion 6.Here conduct is described from the MHP of mixed signal.As shown in Figure 3, establishing specular layer 1013 is L to the distance of object 10, and the oscillation wavelength of laser is λ, and when satisfying following resonant condition, the laser in the optical resonator of the back light of object 10 and semiconductor laser 1 strengthens mutually, makes laser output that increase be arranged slightly.
L=qλ/2…(1)
In formula (1), q is an integer.This phenomenon, even from the scattered light of object 10 when very faint, the increase of the reflectivity that embodies in the resonator by semiconductor laser 1 produces amplification, thereby can observe fully.
Fig. 4 is the figure that shows the relation between the output waveform of oscillation wavelength when making the oscillation wavelength of semiconductor laser 1 change with certain certain ratio and photodiode 2.When satisfying the L=q λ that formula (1) shows/2, the phase differential of the laser in back light and the optical resonator is 0 ° (same-phase), laser in back light and the optical resonator is maximum enhancing mutually, when L=q λ/2+ λ/4, phase differential is 180 ° (phase reversals), and the laser in back light and the optical resonator is that maximum weakens mutually.Therefore, if make the oscillation wavelength of semiconductor laser 1 change, laser output alternately repeats the phenomenon that strengthens and weaken, detects the laser output of this moment by light emitting diode 2, can obtain the stair-stepping waveform of some cycles as shown in Figure 4.Such waveform is commonly referred to as interference fringe.This stair-stepping waveform is the MHP that is of each interference fringe.As previously mentioned, when making the oscillation wavelength variation of semiconductor laser 1 within the certain hour, the number of MHP and mensuration distance change with being directly proportional.
Fig. 5 is the block diagram of the configuration example of shows signal extraction unit 7.Signal extraction portion 7 comprises binaryzation portion 70 and period measurement portion 71.
Fig. 6 (A)~Fig. 6 (D) is used for the figure that the action to signal extraction portion 7 describes, Fig. 6 (A) schematically shows the waveform of the output voltage of filtering portion 6, it is the waveform of MHP, Fig. 6 (B) shows the output corresponding to the binaryzation portion 70 of Fig. 6 (A), Fig. 6 (C) is the figure that shows the sampling clock CLK that is input to signal extraction portion 7, and Fig. 6 (D) is the figure of demonstration corresponding to the measurement result of the period measurement portion 71 of Fig. 6 (B).
At first, the output voltage of the filtering portion 6 shown in binaryzation portion 70 process decision charts 6 (A) of signal extraction portion 7 is a still low level (L) of high level (H), and the result of determination of output as Fig. 6 (B).At this moment, binaryzation portion 70 rises at the output voltage of filtering portion 6 and has reached threshold value TH1 and be judged to be high level when above, reached threshold value TH2 and (be judged to be low level during TH2<TH1), thereby make the output binaryzation of filtering portion 6 when the output voltage of filtering portion 6 descends.
The cycle of the rising edge of the output of mensuration binaryzation portion 70 when period measurement portion 71 takes place in each rising edge (, the cycle of MHP).At this moment, period measurement portion 71 is the cycle that a unit measures MHP with the cycle of the sampling clock CLK shown in Fig. 6 (C).In the example of Fig. 6 (D), period measurement portion 71, sequentially determining T α, T β, T γ are as the cycle of MHP.According to Fig. 6 (C), Fig. 6 (D) as can be known, the size of period T α, T β, T γ is respectively 5[samplings], 4[samplings], 2[samplings].The frequency of sampling clock CLK is enough high with respect to the getable highest frequency of MHP.
Then, calculating part 8 is based on the instrumentation result of signal extraction portion 7, according to the displacement and the speed of the change calculations object 10 in cycle of each MHP.Fig. 7 is the block diagram that shows the configuration example of calculating part 8.Calculating part 8 comprises storage part 80, cycle correction portion 81, Physical Quantity Calculation portion 82.
The instrumentation result of storage part 80 storage signal extraction units 7.Before the cycle of MHP in the cycle of the MHP when static with object 10 of cycle correction portion 81, the distance that calculates or this are revised institute's instrumentation to the moving average in cycle of MHP of specified quantity in any one as reference period T0, by this instrumentation result and reference period T0 of comparison signal extraction unit 7, the instrumentation result of signal extraction portion 7 is revised.Fig. 8 (A)~Fig. 8 (F) is the figure that is used to illustrate the action of cycle correction portion 81.
When the period T of the MHP that is obtained by signal extraction portion 7 instrumentations shown in Fig. 8 (A) during less than 0.5T0, the cycle after the period Tn ext of the MHP that cycle correction portion 81 obtains period T and the next instrumentation of MHP shown in Fig. 8 (B) is synthetic is as the period T of revised MHP '.
Again, when the period T of the MHP that is obtained by signal extraction portion 7 instrumentations shown in Fig. 8 (C) during more than 1.5T0 and less than 2.5T0, the cycle that cycle correction portion 81 obtains behind period T two five equilibriums with MHP shown in Fig. 8 (D) is respectively as revised period T 1 ', T2 '.
Again, when shown in Fig. 8 (E) by 7 instrumentations of signal extraction portion to the period T of MHP more than 2.5T0 and in less than 3.5T0, the cycle that cycle correction portion 81 obtains after the period T trisection with MHP shown in Fig. 8 (F) is respectively as revised period T 1 ', T2 ', T3 '.Also be same under the situation more than the 3.5T0.It is cycle correction portion 81, at (m-0.5) more than the T0 and under the situation less than (m+0.5) T0 (m is the natural number more than 2), the cycle of the period T of MHP being carried out obtain behind the branches such as m is respectively as the revised cycle in the period T of the MHP that is obtained by 7 instrumentations of signal extraction portion.Cycle correction portion 81 carries out as above correcting process as a result the time at each signal extraction portion 7 output instrumentations.
Fig. 9 is the instrumentation result's of explanation signal extraction portion 7 the figure of correction principle, and it has schematically shown the output voltage waveforms of filtering portion 6, the i.e. waveform of MHP.
Originally, the cycle of MHP according to object 10 between distance different and different, if but and the distance between the object 10 constant, then MHP occurred with same cycle.Yet because the cause of noise, the waveform of MHP can produce shortcoming, or produce not should signal waveform, thereby causes the cycle of MHP to produce error.
If produce the shortcoming of signal, the period T w that then produces the MHP in the place of being short of is the roughly twice in script cycle.That is, the cycle of MHP be reference period T0 roughly twice is above the time, can be judged as signal and produce shortcoming.Like this, can pass through period T w two five equilibriums, the shortcoming of coming corrected signal.
Again, at the period T s of the MHP in the place of having calculated noise roughly 0.5 times for cycle originally.That is, the cycle of MHP can be judged as the signal-count surplus less than roughly 0.5 times time of reference period T0.Like this, by making period T s and the period Tn ext addition that obtains of instrumentation next time, to error count noise revise.
More than, be the instrumentation result's of signal extraction portion 7 correction principle.In the present embodiment, make that the threshold value be used to determine to be considered as calculating the period T s of noise is 0.5 times the value of reference period T0, make the threshold value of period T w of the shortcoming be used to determine to be considered as producing signal not be 2 times the value of reference period T0, but 1.5 times value, determine 1.5 times reason will after discuss.
Then, Physical Quantity Calculation portion 82 is according to revising displacement and the speed of each cycle of the MHP that obtains with respect to the change calculations object 10 of reference period T0 by cycle correction portion 81.If the frequency of sampling clock is fad[Hz], reference period is T0[samplings], the vibration mean wavelength of semiconductor laser 1 is cycle of λ [m], revised MHP to prolong n[samplings by reference period T0] time, the displacement D[m of object 10 in the cycle of this revised MHP] be shown below.
D=n×λ/(2×T0)…(2)
The cycle of revising back MHP shortens n[samplings by reference period T0] time, make the symbol of cycle variable quantity n of formula (2) get final product for negative.Among first duration of oscillation P1 that the vibration wavelength of semiconductor laser 1 increases, displacement D is timing, and the moving direction of object 10 is the directions away from semiconductor laser 1, when displacement D when negative, the moving direction of object 10 is the direction near semiconductor laser 1.In addition, in second duration of oscillation P2 that oscillation wavelength reduces, when displacement D for just, the moving direction of object 10 be the direction near semiconductor laser 1, when displacement D is when bearing, the moving direction of object 10 is the direction away from semiconductor laser 1.
Again, be (T0+n)/fad owing to revise the cycle of back MHP, the speed V[m/s of object 10 in the cycle of this revised MHP] be shown in the following formula.
V=n×λ/(2×T0)×fad/(T0+n) …(3)
Physical Quantity Calculation portion 82 can calculate the displacement D of object 10 according to formula (2), calculates the speed V of object 10 according to formula (3).For example, if the frequency f ad of sampling clock is 16[MHz], reference period T0 is 160[samplings], the mean wavelength of semiconductor laser 1 is 850[nm], if cycle of revised MHP increases 1[samplings by reference period T0], the displacement D that then can calculate object 10 in cycle of this MHP is 5.31[nm], speed V is 1.05[mm/s].Each cycle of 82 couples of revised MHP of Physical Quantity Calculation portion is carried out computing as described above.
Display part 9 shows the result of calculation of calculating part 8.
Here, making the number of MHP each semiperiod and that be associated with the distance of object 10 of carrier wave (triangular wave) of the oscillation wavelength modulation of semiconductor laser 1 is N1.Then be λ/2 * Na when the absolute value with the maximal rate of object 10 has changed the displacement in each cycle of carrier wave into, the number of the MHP of each carrier wave semiperiod is N1 ± Na.When the displacement in each cycle of carrier wave was moved with the speed of λ/2 * Nb, the number of the MHP of each carrier wave semiperiod was N1+Nb, can observe the cycle of the MHP corresponding with this number like this.For displacement D and the speed V that tries to achieve object 10, can be according to the contrary number of calculating the MHP of each carrier wave semiperiod of cycle of each MHP, and calculate the displacement D and the speed V of object 10 according to the number of this MHP.Above-mentioned formula (2), (3) are based on such derivation principle.
Patent documentation 1 disclosed in mixed type laser instrumentation device, the displacement of object and the resolution characteristic of speed are roughly half wavelength lambda/2 of semiconductor laser.On the other side, in the embodiment of the present invention, because the resolution characteristic of displacement D and speed V is λ/2 * n/T0, therefore can realize resolution characteristic, thereby realize carrying out instrumentation with the resolution characteristic higher than prior art less than wavelength X/2.
As mentioned above, in the present embodiment, the displacement D of object 10 and speed can be carried out instrumentation with the resolution characteristic higher than prior art.Again, patent documentation 1 disclosed in mixed type laser instrumentation device, need expend the instrumentation time of the semiperiod of carrier wave, and in the present embodiment, owing to can try to achieve the displacement D and the speed V of object 10 according to the cycle of each MHP, therefore the needed time of instrumentation can shorten significantly, thereby goes for the fast object of velocity variations 10.Further, in the present embodiment, owing to can revise the error in the cycle of MHP, thus can improve the instrumentation precision of displacement D and speed V.
Because even when object 10 was static, also there was deviation in the cycle of each MHP in normal distribution, therefore moving average etc. is carried out in the displacement that calculates and handled and get final product again.
Again, in the present embodiment, the displacement and the speed of object 10 are carried out instrumentation, but also can be only to wherein one carry out instrumentation.
Then, describe being used to determine to be considered as 1.5 times the reason that threshold value that signal produced the period T w of shortcoming is made as reference period T0.The oscillation wavelength of semiconductor laser 1 be changed to linear change the time, the cycle of MHP is center normal distribution (Figure 10) with reference period T0.
Here, consider MHP waveform generation the situation of shortcoming.Because the cycle of MHP is the normal distribution at center with T0 originally, be the normal distribution (f among Figure 11) of mean value 2T0, standard deviation 2 σ so when instrumentation, produced the cycle of the MHP when being short of because the intensity of MHP is little.When being short of j[%] MHP the time, in any of first duration of oscillation P1 or second duration of oscillation P2, the number of 7 couples of MHP of signal extraction portion is counted, its result, when the number of MHP is N, be Nw (=j[%] N) because this shortcoming cycle is the number of degrees in cycle of 2 times MHP.Again, because the number of degrees in the cycle that be roughly T0 of the shortcoming during instrumentation after reducing are as shown in figure 11 g, the reduction of the number of degrees shown in the h of Figure 11 is 2Nw (=2j[%]).Therefore, in any in first duration of oscillation P1 and second duration of oscillation P2, the number N ' of the MHP of the script when not producing the MHP shortcoming can represent with following formula.
N’=N+j[%]=N+Nw …(4)
Then, consider to be used to revise instrumentation result's the threshold value in the cycle of MHP.What suppose is because the shortcoming cycle during instrumentation is p[% among 2 times the number of degrees Nw in cycle of MHP herein ,] situation about being divided into two by noise.The number of degrees in the cycle of the MHP that is divided into two among the MHP that has been short of are Nw ' (=jp[%] N).The number of degrees in the cycle of the MHP that is divided into two once again distribute as shown in figure 12.Be made as 1.5T0 if will be considered as the threshold value in the cycle of Nw, then the number of degrees in the cycle of the following MHP of cycle 0.5T0 are 0.5Nw ' (=0.5p[%] Nw), cycle are 0.5T0 to the number of degrees in the cycle of the MHP of 1.5T0 to be Nw ' (=p[%] Nw), and the cycle is that the number of degrees in the cycle of the above MHP of 1.5T0 are 0.5Nw ' (=0.5p[%] Nw).
Therefore, the number of degrees in the cycle of all MHP distribute as shown in figure 13, and the threshold value of establishing the number of degrees Ns in the cycle corresponding with above-mentioned Ts is 0.5T0, and when the threshold value of the number of degrees Nw in the cycle corresponding with above-mentioned Tw was 1.5T0, count results N can represent with following formula.
N=(N’-2Nw)+(Nw-Nw’)+2Nw’=N’-Nw+Nw’
…(5)
According to formula (5), revised result as shown below, the number N ' that does not produce under the situation of MHP shortcoming MHP originally during counting can calculate.
N-0.5Nw’+(0.5Nw’+(Nw-Nw’))
=(N-Nw+Nw’)+(0.5Nw’+(Nw-Nw’))
=N’ …(6)
According to more than, if the threshold value in the cycle when make calculating number of degrees Nw is 1.5 times of reference period T0, then can revise count results N.If the sampling clock number of each semiperiod of triangular wave is M, the relation that then has T=M/N between the period T of MHP and the count results N, because M is a certain value, as can be known, the threshold value of period T w that is used to determine to be considered as to produce the signal shortcoming is identical with the situation of count results N, can be 1.5 times of reference period T0.
Again, in the present embodiment, reference period T0 is made as the cycle of the MHP under object 10 stationary states, but is not limited thereto, and the moving average in the cycle of the MHP of the regulation number that calculating part 8 also can obtain institute's instrumentation before revising is as reference period T0.According to this method, though object 10 can't be static situation under, also can try to achieve reference period T0.
Second embodiment
Then, second embodiment of the present invention is described.Figure 14 is the block diagram of the configuration example of the calculating part 8 that shows that second embodiment relates to.Calculating part 8 comprises storage part 80, cycle correction portion 81, Physical Quantity Calculation portion 82, count section 83, distance calculation portion 84, computation of Period portion 85.The whole formation of physical quantity transducer is identical with first embodiment, but the pace of change of the oscillation wavelength of semiconductor laser 1 is certain, and the maximal value λ b of oscillation wavelength and the minimum value λ a of oscillation wavelength are respectively necessarily, and its difference λ b-λ a also needs for necessarily.
Count section 83 is counted the number of the MHP in the output that is included in filtering portion 6 respectively at first duration of oscillation P1 and second duration of oscillation P2.Count section 83 can be utilized the counter that is made of logic gate, also can utilize FFT (Fast FourierTransform) that the frequency (that is the number of MHP in the unit interval) of MHP is carried out instrumentation.
Then, the number of the MHP that the minimum oscillation wavelength lambda a of distance calculation portion 84 based semiconductor laser instruments 1 and full swing wavelength X b and count section 83 are counted to get is calculated the distance with object 10.In the present embodiment, the state of object 10 can be the micro-displacement state that satisfies rated condition, or moves any in the big displacement state than micro-displacement state.When the average displacement of the object 10 during each of duration of oscillation P1 and vibration period P 2 is made as V, that the micro-displacement state is meant is satisfied (λ b-λ a)/state of λ b>V/Lb (but, distance when Lb is meant t constantly), that displacement state is meant is satisfied (λ b-λ a)/state of λ b≤V/Lb.
At first, candidate value L α (t), the L β (t) of the distance of distance calculation portion 84 as following formula calculating t now and candidate value V α (t), the V β (t) of speed.
Lα(t)=λa×λb×(MHP(t-1)+MHP(t))
/{4×(λb-λa)} …(7)
Lβ(t)=λa×λb×(|MHP(t-1)-MHP(t)|)/{4×(λb-λa)} …(8)
Vα(t)=(MHP(t-1)-MHP(t))×λb/4 …(9)
Vβ(t)=(MHP(t-1)+MHP(t))×λb/4 …(10)
In formula (7)~(10), MHP (t) is the number of the MHP that t is calculated now, and MHP (t-1) is meant the number at the preceding MHP that is once calculated of MHP (t).For example, if MHP (t) is the count results of first duration of oscillation P1, MHP (t-1) is the count results of second duration of oscillation P2, otherwise, if MHP (t) is the count results of second duration of oscillation P2, then MHP (t-1) is the count results of first duration of oscillation P1.
Candidate value L α (t), V α (t) are the values that is calculated when supposing object 10 for the micro-displacement state, and candidate value L β (t), V β (t) are the values that is calculated when supposing object 10 for displacement state.Distance calculation portion 84 carries out the calculating of formula (7)~(10) in each moment (each duration of oscillation) of measuring by the number of 83 couples of MHP of count section.
Then, 84 pairs of micro-displacement states of distance calculation portion and displacement state, the difference of calculating between the candidate value of candidate value and the distance in the moment before of distance of t now by following formula is historical displacement respectively.Again, in formula (11), formula (12), now, the candidate value of the preceding distance that is once calculated of t was L α (t-1), L β (t-1).
Vcalα(t)=Lα(t)-Lα(t-1) …(11)
Vcalβ(t)=Lβ(t)-Lβ(t-1) …(12)
The value that historical displacement Vcal α (t) calculates when being the micro-displacement state for hypothesis object 10, historical displacement Vcal β (t) is the value that calculates when supposing object 10 for displacement state.Distance calculation portion 84 carries out the calculating of formula (11)~formula (12) constantly at each of the number of being measured MHP by count section 83.Again, in formula (9)~formula (12), object 10 is defined as positive speed near the direction of the physical quantity transducer of present embodiments, will away from direction be defined as negative velocity.
Then, distance calculation portion 84 adopts the result of calculation of formula (7)~formula (12), judges the state of object 10.
As patent documentation 1 is put down in writing, the symbol of the historical displacement Vcal α (t) that obtains in the micro-displacement state computation at hypothesis object 10 is for certain, and when the average absolute of supposing the candidate value V α (t) of the speed that object 10 obtains in the micro-displacement state computation and historical displacement Vcal α (t) equated, distance calculation portion 84 was judged to be object 10 and is the uniform motion with the micro-displacement state.
Again, as patent documentation 1 record, the symbol of the historical displacement Vcal β (t) that calculates at displacement state at hypothesis object 10 is for certain, and when the average absolute of supposing the candidate value V β (t) of the speed that object 10 calculates at displacement state and historical displacement Vcal β (t) equated, distance calculation portion 84 was judged to be object 10 and is the uniform motion with displacement state.
Again, as patent documentation 1 record, the symbol of the historical displacement Vcal α (t) that obtains in the micro-displacement state computation at hypothesis object 10 is in each counter-rotating constantly of the number of measuring MHP, and when the average absolute of supposing the candidate value V α (t) of the speed that object 10 obtains in the micro-displacement state computation and historical displacement Vcal α (t) was inconsistent, distance calculation portion 84 was judged to be object 10 and does motion beyond the uniform motion with the micro-displacement state.
Again, if be conceived to the candidate value V β (t) of speed, the absolute value of V β (t) is a constant, this value and the wavelength variable quantity of semiconductor laser 1 (λ b-λ a)/λ b is equal.At this moment, absolute value and wavelength variations rate at the candidate value V β (t) that supposes the speed that object 10 calculates at displacement state equate, and when the average absolute of supposing the candidate value V α (t) of the speed that object 10 calculates at the micro-displacement state and historical displacement Vcal α (t) was inconsistent, distance calculation portion 84 was judged to be object 10 and does motion beyond the uniform motion with the micro-displacement state.
Again, put down in writing as patent documentation 1, measure moment counter-rotating of the number of MHP at the symbol of supposing the historical displacement Vcal β (t) that object 10 calculates at displacement state at each, and when the average absolute of supposing the candidate value V β (t) of the speed that object 10 calculates at displacement state and historical displacement Vcal β (t) was inconsistent, distance calculation portion 84 was judged to be object 10 and does motion beyond the uniform motion with displacement state.
Again, if be conceived to the candidate value V α (t) of speed, the absolute value of V α (t) is a constant, this value and the wavelength variations rate of semiconductor laser 1 (λ b-λ a)/λ b is equal.Thereby distance calculation portion 84, absolute value at the candidate value V α (t) that supposes the speed that object 10 calculates at the micro-displacement state equates with the wavelength variations rate, and when the average absolute of supposing the candidate value V β (t) of the speed that object 10 calculates at displacement state and historical displacement Vcal β (t) was inconsistent, decidable object 10 was done motion beyond the uniform motion with displacement state.
Distance calculation portion 84 determine according to above-mentioned result of determination and object 10 between distance.Promptly, distance calculation portion 84 is being judged to be object 10 when being the uniform motion with the micro-displacement state, with the candidate value L α (t) of distance as with the distance of object 10, when being judged to be object when being the uniform motion with displacement state, with the candidate value L β (t) of distance as with the distance of object 10.
Again, distance calculation portion 84 is being judged to be object 10 when doing motion beyond the uniform motion with the micro-displacement state, with the candidate value L α (t) of distance as with the distance of object 10.Yet actual distance is the mean value of the candidate value L α (t) of distance.Again, distance calculation portion 84 is being judged to be object when doing motion beyond the uniform motion with displacement state, with the candidate value L β (t) of distance as with the distance of object 10.But actual distance is the mean value of the candidate value L β (t) of distance.
Then, the distance that calculated according to distance calculation portion 84 of computation of Period portion 85 is tried to achieve the cycle of MHP.The frequency of MHP and mensuration distance are directly proportional, and the cycle of MHP and mensuration distance are inversely proportional to.Here, try to achieve the relation of the cycle of MHP and distance in advance and be stored in words in the database (not shown) of computation of Period portion 85, the cycle of MHP can be tried to achieve by obtain the cycle of the corresponding MHP of distance that is calculated with distance calculation portion 84 from database by computation of Period portion 85.Perhaps, if try to achieve in advance and set the expression MHP cycle and the distance between the relation formula, computation of Period portion 85 can bring numerical expression into by the distance that distance calculation portion 84 is calculated, and tries to achieve the cycle of MHP.
The cycle that computation of Period portion 85 is tried to achieve by cycle correction portion 81 is as reference period T0, the instrumentation result of signal extraction portion 7 revised to get final product as illustrating in first embodiment.The action of Physical Quantity Calculation portion 82 is identical with first embodiment.In the present embodiment, even also can try to achieve reference period T0 under the static situation of object 10 can't making.
The 3rd embodiment
Then, the 3rd embodiment of the present invention is described.Figure 15 is the block diagram of the configuration example of the calculating part 8 that relates to of third embodiment of the invention.Calculating part 8 has: storage part 80; Cycle correction portion 81; Physical Quantity Calculation portion 82; The count section 86 that the number of MHP in the output voltage that is included in filtering portion 6 is counted; The storage part 87 of the count results of stored count portion 86 etc.; The mean value of the count results by count portion 86, try to achieve with semiconductor laser 1 and object 10 between the distance proportion number calculating part 88 of number (below be called the distance proportion number) NL of the MHP that is directly proportional of mean distance; Symbol assigning unit 89, it is according to the previous count results of count section 86 and use the magnitude relationship of two multiples of the distance proportion number NL that calculates than this count results count results more before, gives sign symbol to the most recent count result of count section 86; Calculate the computation of Period portion 90 in the cycle of MHP according to distance proportion number NL.The one-piece construction of physical quantity transducer can be with first embodiment identical.
Count section 86 is counted the number of the MHP in the output that is contained in filtering portion 6 respectively at first duration of oscillation P1 and second duration of oscillation P2.Count section 86 can adopt the counter that is made of logic gate, also can be the device that adopts FFT that the frequency (being the number of MHP in the unit interval) of MHP is counted.The count results of count section 86 is stored in the storage part 87.
Distance proportion number calculating part 88 is tried to achieve distance proportion number NL according to the count results of count section 86.Figure 16 is the figure that the action of ratio number calculating part 88 describes that adjusts the distance, and its time that has shown the count results of count section 86 changes.In Figure 16, Nu is the count results of first duration of oscillation P1, and Nd is the count results of second duration of oscillation P2.The range rate of object 10 is littler than the oscillation wavelength rate of change of semiconductor laser 1, and when object 10 was done simple harmonic oscillation, the time of count results Nu changed and the time variation of count results Nd is the sinusoidal waveforms of 180 degree as shown in figure 16 for mutual phase differential.In the patent documentation 1, with this moment object 19 state as the micro-displacement state.
As shown in Figure 21, because first duration of oscillation P1 and second duration of oscillation P2 alternately occur, count results Nu and count results Nd also alternately occur.Count results Nu, Nd be, the number of distance proportion number NL and the MHP that is directly proportional with the displacement of object (below be called displacement ratio number) be NV's and or poor.Distance proportion number NL is equivalent to sine-shaped mean value shown in Figure 16.Again, count results Nu or Nd and distance proportion number NL's is poor, is equivalent to displacement ratio number NV.
Distance proportion number calculating part 88, by as following formula to institute's instrumentation till now preceding twice of t to the mean value of even number time count results calculate, come computed range ratio number NL.
NL={N(t-2)+N(t-3)}/2 …(13)
In the formula (13), the number N of the MHP that preceding twice instrumentation of N (t-2) expression t now obtains, the number N of the MHP that first three time institute instrumentation of N (t-3) expression t now obtains.If now, the count results N (t) of t was the count results Nu of the first vibration period P 1, then preceding twice count results N (t-2) also is the count results Nu of first duration of oscillation P1, and the count results N (t-3) of first three time is the count results Nd of second duration of oscillation P2.On the contrary, if now, the count results N (t) of t was the count results Nd of the second vibration period P 2, then preceding twice count results N (t-2) also is the count results Nd of second duration of oscillation P2, and the count results N (t-3) of first three time is the count results Nu of first duration of oscillation P1.
Formula (13) is to ask the formula of the situation of distance proportion number NL with twice count results, and under the situation of using the inferior count results of 2m (m is positive integer), distance proportion number calculating part 88 is as shown in the formula computed range ratio number NL like that.
NL={N(t-2m-1)+N(t-2m)+…+N(t-2)}/2m
…(14)
But, formula (13), formula (14) be used for and object 10 between distance and the instrumentation of the speed of object 10 begin employed formula of initial stage, use the following formula of described later signed count results to replace formula (13) from adopting midway, thereby carry out the calculating of distance proportion number NL.
NL={N’(t-2)+N’(t-3)}/2 …(15)
N ' is preceding twice count results N (t-2) to be carried out symbol described later give processing signed count results afterwards (t-2), and N ' is first three inferior count results N (t-3) to be carried out symbol described later give processing signed count results afterwards (t-3).Formula (15) is used become the count results that begins the 7th time from the number instrumentation of MHP at the count results N of t now (t) after.
Again, the instrumentation initial stage that begins adopts under the situation of formula (14), begins not adopt formula (14) midway, and adopts the following formula computed range ratio number NL that uses signed count results.
NL={N’(t-2m-1)+N’(t-2m)+…+N’(t-2)}/2m
…(16)
Formula (16) becomes at the count results N of t now (t) and begins the from the number instrumentation of MHP (to be used after the inferior count results of 2m * 2+3).
Distance proportion number NL is stored in storage part 87.Distance proportion number calculating part 88 carries out the computing of distance proportion number NL as above in each moment (each oscillation period) by the number of count section 86 mensuration MHP.
In addition, be used for the count results of calculating of distance proportion number NL when abundant, also can come computed range ratio number NL with the count results of odd number time.
Then, symbol assigning unit 89 according to now t the count results N (t-1) that obtains of preceding once institute instrumentation and the magnitude relationship of the 2 multiple 2NL of distance proportion number NL, give sign symbol to the count results N (t) of count section 86.The following formula of symbol assigning unit 89 concrete execution.
If N (t-1) 〉=2NL so N ' (t) →-N (t) ... (17)
If N (t-1)<2NL so N ' (t) →+N (t) ... (18)
Figure 17 is the action that is used to illustrate symbol assigning unit 9, and the figure of the time variation of the count results of demonstration count section 86.When the range rate of object 10 is bigger than the oscillation wavelength rate of change of semiconductor laser 1, the time of count results Nu be changed to Figure 17 170 shown in the turn back shape of positive side of the waveform of minus side, the time of same count results Nd be changed to Figure 17 171 shown in the turn back shape of positive side of the waveform of minus side.In the patent documentation 1, the state of object 10 that produces the part of turning back of this count results is a displacement state.On the other hand, the state of object 10 that does not produce the part of turning back of count results is described micro-displacement state.
In order to try to achieve the physical quantity of object 10 in the vibration that comprises displacement state, judge that object 10 still is the micro-displacement state for displacement state, when object 10 is displacement state, the count results of turning back to positive side as Figure 17 170,171 shown in track need like that to revise.Formula (17), formula (18) are to be used to judge that object 10 is formulas of displacement state or micro-displacement state.Under the displacement state that the generation count results is turned back in Figure 17, N (t-1) 〉=2NL sets up.Thereby, shown in formula (17), when N (t-1) 〉=2NL sets up, to count section 86 now t count results N (t) give minus symbol, as signed count results N ' (t).
On the other hand, do not produce in Figure 16 and Figure 17 under the micro-displacement state that count results turns back, N (t-1)<2NL sets up.Thereby, shown in formula (18), when N (t-1)<2NL sets up, to count section 86 now t count results N (t) for having given plus sign, (t) as signed count results N '.
Signed count results N ' (t) is stored in storage part 87.Symbol assigning unit 89 was carried out symbol as described above and is given processing in each moment (each oscillation period) by the number of count section 86 mensuration MHP.
Again, the establishment condition of formula (17) can be N (t-1)>2NL, and the establishment condition of formula (18) can be N (t-1)≤2NL.
Then, computation of Period portion 90 is shown below according to distance proportion number NL and calculates the period T of MHP.
T=C/(2×f×NL) …(19)
Herein, f is the triangle wave frequency, and C is the light velocity.
The cycle that cycle correction portion 81 calculates with computation of Period portion 90, the instrumentation result to signal extraction portion 7 as first embodiment is illustrated revised as reference period T0.The action of Physical Quantity Calculation portion 82 is identical with first embodiment.In the present embodiment, even, also can try to achieve reference period T0 making under the static situation of object 10.
The 4th embodiment
Then, the 4th embodiment of the present invention is described.In first~the 3rd embodiment, make semiconductor laser 1 vibration wavy, but be not limited thereto, can make as shown in figure 18 in the 3rd embodiment that also semiconductor laser 1 vibration is wavy for sawtooth for triangle.That is, in the present embodiment, among the win duration of oscillation P1 or second duration of oscillation P2 any occurred repeatedly as long as drive semiconductor laser 1.But, in second embodiment, need make semiconductor laser 1 vibration wavy for triangle.
Even make semiconductor laser 1 vibration as present embodiment is that it is certain that the pace of change of the oscillation wavelength of semiconductor laser 1 also needs under the wavy situation of sawtooth.Action in first duration of oscillation P1 or the second vibration period P 2 is identical with the situation of triangular wave oscillation.Also can be as shown in figure 18, only under the situation of the wavy vibration of the sawtooth that repeats of first duration of oscillation P1, repeat the processing of first duration of oscillation P1, certainly, only under the situation of the wavy vibration of the sawtooth that repeats of second duration of oscillation P2, also can repeat the processing of second duration of oscillation P2.
The 5th embodiment
Then, the 5th embodiment of the present invention is described.In first~the 4th embodiment,, also can not adopt photodiode to extract the MHP waveform though adopt photodiode 2 and current-voltage conversion enlarging section 5 to comprise the detecting unit of the electric signal of MHP waveform as detection.Figure 19 is the block diagram of the formation of the physical quantity transducer that shows that the 5th embodiment of the present invention relates to, the structure mark same symbol identical with Fig. 1.The physical quantity transducer of present embodiment adopts voltage detection department 12 as detecting unit, replaces photodiode 2 and current-voltage conversion enlarging section 5 in first embodiment.
The voltage between terminals of voltage detection department 12 noise spectra of semiconductor lasers 1, promptly voltage detects and amplifies between anode-cathode.The laser of being launched by semiconductor laser 1 and the back light of object 10 produce when interfering, and the MHP waveform appears in the voltage between terminals of semiconductor laser 1.Thereby, can extract the MHP waveform from the voltage between terminals of semiconductor laser 1.Carrier wave is removed from the output voltage of voltage detection department 12 by filtering portion 6.Other structures of physical quantity transducer and first embodiment identical.
Like this, in the present embodiment, can not use the photodiode extraction MHP waveform and the first embodiment comparison can reduce the number of components of physical quantity transducer, thereby reduce the manufacturing cost of physical quantity transducer.Again, in the present embodiment, owing to do not adopt photodiode, thus the influence that can remove stray light.
Again, in first~the 5th embodiment at least signal extraction portion 7 and calculating part 8 can by, for example, have the computing machine of CPU, storer and interface and program that these hardware resources are controlled realizes.CPU carries out illustrated processing in first~the 5th embodiment according to the program that is stored in the storer.

Claims (14)

1. a physical quantity transducer is characterized in that, comprising:
Semiconductor laser to determination object emission laser;
The oscillation wavelength modulating unit starts described semiconductor laser, makes during continuously dull first vibration that increases of oscillation wavelength and at least a in dull continuously second duration of oscillation that reduces of vibration wavelength occurs repeatedly;
Detecting unit, its detection comprises the electric signal of interference waveform, and described interference waveform is produced by the self-mixing effect from the back light of described semiconductor laser emitted laser and described determination object;
Signal extraction unit, it carries out instrumentation to the cycle of the described interference waveform in the output signal that is included in this detecting unit when the described interference waveform of each input;
The cycle correction unit, it is revised described instrumentation result by the instrumentation result of this signal extraction unit and reference period are compared;
Computing unit, it calculates the displacement of described determination object and at least one item in the speed based on by revised each cycle of this cycle correction unit.
2. physical quantity transducer as claimed in claim 1, it is characterized in that, described computing unit, according to the mean wavelength of the frequency of the sampling clock in cycle of the described interference waveform of instrumentation, described reference period, described semiconductor laser, by the variable quantity of revised cycle of described cycle correction unit, calculate at least one in the displacement of described determination object and the speed with respect to described reference period.
3. physical quantity transducer as claimed in claim 1 or 2, it is characterized in that, described cycle correction unit, by described signal extraction unit instrumentation to cycle of interference waveform during less than stated number k times of described reference period, wherein k be less than 1 on the occasion of, then with the cycle of this interference waveform with the waveform that combined cycle is obtained is as a waveform as the cycle of revised interference waveform the cycle of the cycle of the interference waveform that obtains of institute's instrumentation after merging afterwards; By described signal extraction unit instrumentation to cycle of interference waveform be described reference period (m-k) doubly more than and during less than (m+k) of described reference period times, wherein m is the natural number more than 2, the cycle that obtains behind the branches such as period m with this interference waveform, the waveform in revised cycle had m respectively as the revised cycle.
4. physical quantity transducer as claimed in claim 3 is characterized in that, described stated number k is 0.5.
5. as any physical quantity transducer of being put down in writing in the claim 1 to 4, it is characterized in that, described cycle correction unit, the cycle of the described interference waveform with described determination object when static or described be about to revise before the mean value in cycle of interference waveform of the stated number that arrives of institute's instrumentation as described reference period.
6. as any described physical quantity transducer in the claim 1 to 4, it is characterized in that, also comprise:
Counting unit, it is counted respectively in described first duration of oscillation and described second duration of oscillation the number of the described interference waveform in the output signal that is included in described detecting unit;
Metrics calculation unit, its according to by this counting unit to the number of interference waveform count during the count results of minimum oscillation wavelength, full swing wavelength and described counting unit calculate and described determination object between distance;
The computation of Period unit, it tries to achieve cycle of described interference waveform according to the distance that this metrics calculation unit calculated,
Described cycle correction unit, the cycle that described computation of Period unit is tried to achieve is as described reference period.
7. as any physical quantity transducer of being put down in writing in the claim 1 to 4, it is characterized in that, also comprise:
Counting unit, it is counted respectively in described first duration of oscillation and described second duration of oscillation the number of the described interference waveform in the output signal that is included in described detecting unit;
Distance proportion number computing unit, the mean value of its number by calculating described interference waveform, the number of trying to achieve with the proportional interference waveform of mean distance of described semiconductor laser and described determination object is the distance proportion number;
The computation of Period unit, the cycle that it calculates described interference waveform according to described distance proportion number,
The cycle that described computation of Period unit is tried to achieve in described cycle correction unit is as described reference period.
8. a physical quantity measuring method is characterized in that, comprising:
The vibration step starts described semiconductor laser, makes oscillation wavelength first duration of oscillation and at least a repeatedly appearance of vibration wavelength in dull continuously second duration of oscillation that reduces of dullness increase continuously;
Detect step, detect the electric signal that comprises interference waveform, described interference waveform is produced by the self-mixing effect from the back light of described semiconductor laser emitted laser and determination object;
The signal extraction step is carried out instrumentation to the cycle that is contained in the described interference waveform in the output signal that described detection step obtains at every turn when importing interference waveform;
The cycle correction step compares by instrumentation result and reference period with this signal extraction step, and described instrumentation result is revised;
Calculation procedure based on revised each cycle of this cycle correction step, calculates the displacement of described determination object and at least one item in the speed.
9. physical quantity measuring method as claimed in claim 8, it is characterized in that, described calculation procedure, according to the frequency of the sampling clock in cycle of the described interference waveform of instrumentation, described reference period, the mean wavelength of described semiconductor laser, variable quantity, calculate at least one in the displacement of described determination object and the speed in the described revised cycle of cycle correction step with respect to described reference period.
10. physical quantity measuring method as claimed in claim 8 or 9, it is characterized in that, described cycle correction step, by described signal extraction step instrumentation to cycle of interference waveform during less than stated number k times of described reference period, wherein k be less than 1 on the occasion of, then with the cycle of this interference waveform with the waveform that the merging cycle is obtained is as a waveform as the cycle of revised interference waveform the cycle of the cycle of the interference waveform that obtains of institute's instrumentation after merging afterwards; By described signal extraction step instrumentation to cycle of interference waveform be described reference period (m-k) doubly more than and during less than (m+k) of described reference period times, wherein m is the natural number more than 2, then the cycle that obtains behind the branches such as period m with this interference waveform is respectively as the revised cycle, and the waveform in revised cycle has m.
11. physical quantity measuring method as claimed in claim 10 is characterized in that, described stated number k is 0.5.
12. as any physical quantity measuring method of being put down in writing in the claim 8 to 11, it is characterized in that, described cycle correction step, the cycle of the described interference waveform with described determination object when static or described be about to revise before the mean value in cycle of interference waveform of the stated number that arrives of institute's instrumentation as described reference period.
13. as any described physical quantity measuring method in the claim 8 to 11, it is characterized in that, also comprise:
Counting step to being contained in the number of the described interference waveform in the output signal that described detection step obtains, is counted respectively in described first duration of oscillation and described second duration of oscillation;
The distance calculation step, according to by this counting step to the number of interference waveform count during the count results of minimum oscillation wavelength, full swing wavelength and described counting step calculate and described determination object between distance;
The computation of Period step, the distance that is calculated according to described distance calculation step is tried to achieve the cycle of described interference waveform,
Described cycle correction step, the cycle that described computation of Period step is tried to achieve is as described reference period.
14. as any physical quantity measuring method of being put down in writing in the claim 8 to 11, it is characterized in that, also comprise:
Counting step to being contained in the number of the described interference waveform in the output signal that described detection step obtains, is counted respectively in described first duration of oscillation and described second duration of oscillation;
Distance proportion number calculation procedure, the mean value of the number by calculating described interference waveform, the number of trying to achieve the interference waveform that is directly proportional with the mean distance of described semiconductor laser and described determination object is the distance proportion number;
The computation of Period step, the cycle of calculating described interference waveform according to described distance proportion number,
The cycle that described cycle correction step is tried to achieve described computation of Period step is as described reference period.
CN2010101314864A 2010-03-04 2010-03-04 Physical quantity transducer and physical quantity measuring method Expired - Fee Related CN102192707B (en)

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Cited By (6)

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CN106643543A (en) * 2016-12-30 2017-05-10 东北石油大学 Method for detecting deformation of surface of magnetic disk storage
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CN115079145A (en) * 2022-08-18 2022-09-20 深圳煜炜光学科技有限公司 Method and device for improving anti-interference capability of laser radar

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US8996326B2 (en) 2009-06-29 2015-03-31 Azbil Corporation Counting device, physical quantity sensor, counting method, and physical quantity measuring method
CN102792183A (en) * 2010-03-10 2012-11-21 阿自倍尔株式会社 Physical quantity sensor and physical quantity measuring method
US8982336B2 (en) 2010-03-10 2015-03-17 Azbil Corporation Physical quantity sensor and physical quantity measuring method
CN105759072A (en) * 2014-12-02 2016-07-13 财团法人工业技术研究院 Optical anemometry system
CN105759072B (en) * 2014-12-02 2020-04-14 财团法人工业技术研究院 Optical anemometry system
CN106643543A (en) * 2016-12-30 2017-05-10 东北石油大学 Method for detecting deformation of surface of magnetic disk storage
CN111637906A (en) * 2020-05-11 2020-09-08 清华大学深圳国际研究生院 Fiber grating demodulation device and method based on self-differencing coherence
CN115079145A (en) * 2022-08-18 2022-09-20 深圳煜炜光学科技有限公司 Method and device for improving anti-interference capability of laser radar

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