JP3246280B2 - Method for measuring impedance characteristics of piezoelectric components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the impedance characteristics of a piezoelectric component, particularly a piezoelectric component used in an oscillation circuit or a resonance circuit.

[0002]

Conventionally, the resonance frequency f _r of the piezoelectric ceramic resonator, the anti-resonance frequency f _a, when measuring the resonance impedance Z _r and antiresonant impedance Z _a is a resonant frequency f _r and the antiresonance frequency f _a a frequency region including sampled at a constant frequency pitch, resonance frequency f _r consider impedance values obtained for each sampling, the anti-resonance frequency f _a, had sought resonance impedance Z _r and the anti-resonance impedance Z _a .

[0003]

However, in the conventional method, since the frequency domain is sampled at a constant frequency pitch, a long time is required for the measurement, and the measurement is wasteful. Because the actually required impedance values, and only those of the resonance frequency f _r and the antiresonance frequency f _a vicinity of the rest of the measurement data is do not require almost.

Accordingly, an object of the present invention is to provide a method for measuring the impedance characteristic of a piezoelectric component, which can improve the efficiency of the measurement and can easily increase the measurement accuracy.

[0005]

Means for Solving the Problems] To achieve the above object, the impedance characteristic measurement method of a piezoelectric component according to the present invention, the piezoelectric component of the phase in (a) predetermined frequency pitch Delta] f _S 0
Sampling the frequency domain including the frequency that becomes ゜ and measuring the sampling frequency f ₁ and its phase φ ₁ before passing through the phase 0 °, and the sampling frequency f ₂ and its phase φ ₂ after passing through the phase 0 ° (B) the provisional resonance frequency f _r1 and the provisional anti-resonance frequency f _a1
One of the frequency, and deriving with the relation f _r1 or _{f a1 = f 1 + (Δf} S · φ 1) / (φ 1 -φ 2), (c) a resonance frequency of the provisional the phase of the piezoelectric component in the f _r1 φ5
Or the phase φ6 of the piezoelectric component at the temporary anti-resonance frequency f _a1
And (d) the phase φ5 or φ6 is within a predetermined phase tolerance.
At some point, the provisional resonance frequency _fr1 or the provisional anti-resonance
Measuring the impedance of the piezoelectric component at the frequency f _a1 .

[0006] The impedance characteristic measuring method of a piezoelectric component according to the present invention, (e) at a slightly smaller frequency pitch Delta] f _S from the difference between Delta] f of the resonance frequency f _r and the antiresonance frequency f _a of the piezoelectric component, piezoelectric component phase Is sequentially sampled from the low frequency side including the frequency at which 0 ° is reached, and the sampling frequency f ₁ and its phase φ ₁ before first passing through the phase 0 °, and the sampling frequency f ₁ after passing through the phase 0 ° first. The sampling frequency f ₂ and its phase φ ₂ , the sampling frequency f ₃ and its phase φ ₃ before passing through the phase 0 ° again, and the sampling frequency f ₄ and its phase φ ₄ after passing through the phase 0 ° again Measuring, and ( f ) the provisional resonance frequency f _r1 and the provisional anti-resonance frequency f _a1 ,
Derived using respective relationship _{f r1 = f 1 + (Δf} S · φ 1) / (φ 2 -φ 1) f a1 = f 3 + (Δf S · φ 3) / (φ 3 -φ 4) process and, (g) said temporary piezoelectric component at the resonant frequency f _r1 phase φ5
And the phase φ6 of the piezoelectric component at the provisional anti-resonance frequency f _a1.
And (h) determining that the phases φ5 and φ6 are within a predetermined phase tolerance.
The provisional resonance frequency _fr1 and the provisional anti-resonance frequency _fa1
And measuring the impedance of the piezoelectric component. Further, the piezoelectric component according to the present invention
The impedance characteristic measuring method is based on the phase φ5 and the phase φ5.
At least one phase of φ6 is out of the specified tolerance
At some point, the phase within the tolerance was also obtained using interpolation.
Until the above steps are repeated.

[0007]

[Action] above method is a method in which the phase of the resonant frequency f _r and the antiresonance frequency f _a is utilized to become 0 °, respectively. Then, sampling is performed at a smaller frequency pitch as the frequency approaches the phase 0 °. Therefore,
Regardless of whether it is in the vicinity of the resonance frequency f _r and the antiresonance frequency f _a, as compared with the conventional method which has been sampled at a constant frequency pitch unnecessary frequency, without waste, and the accuracy Good measurements are made quickly.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for measuring impedance characteristics of a piezoelectric component according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a graph showing an impedance curve 1 and a phase curve 2 of a piezoelectric ceramic vibrator. The impedance curve 1 and the phase curve 2 show typical values of the piezoelectric ceramic vibrator. The piezoelectric ceramic vibrator, a current flowing through the vibrator at the resonance frequency f _r is to become the maximum, the impedance is minimized. on the other hand,
At the anti-resonance frequency f _a , the current flowing in the vibrator is minimized and the impedance is maximized. It refers to the former and resonant impedance Z _r, the latter is called anti-resonance impedance Z _a. The piezoelectric ceramic resonator, the resonance frequency f _r and the antiresonance frequency f _a in the phase becomes 0 °.

[0009] or more characteristics individual resonance of the piezoelectric ceramic resonator having a (typical) frequency f _r1, the antiresonance frequency f _a1, explaining the method of obtaining the resonance impedance Z _r and antiresonant impedance Z _a. First, derived on the basis of a difference Δf of the piezoelectric resonant frequency (typical) of the ceramic resonator f _r and the anti-resonance frequency (typical) f _a in FIG.

Next, as shown in FIG. 2, the phase characteristics of the piezoelectric ceramic vibrator are sampled sequentially from the low frequency side at a frequency pitch Δf _S slightly smaller than Δf. The sampling area at this time is the resonance frequency (representative value) _fr
And the anti-resonance frequency (representative value) f _a . As a result, a frequency region including a frequency at which the phase becomes 0 ° is sampled. Further, it is preferable that the sampling area be approximately 2Δf _S. This is because the number of samplings can be reduced and the measurement can be performed more quickly. However, the frequency pitch Δf _S is not limited to this, and the phase characteristics may be sampled at a frequency pitch such as や or の of Δf.

Then, the sampling frequency f ₁ before passing through the phase 0 ° and its phase φ ₁ are measured first, and the sampling frequency f ₂ after passing through the phase 0 ° and its phase φ ₂ are measured first. The sampling frequency f ₃ before passing through the phase 0 ° again and its phase φ ₃ are measured, and the sampling frequency f ₄ after passing through the phase 0 ° again and its phase φ ₄ are measured. However, in the present embodiment, since the reduced number of samples to be able to quickly carry out the measurement, the sampling frequency f ₂ and f ₃ become equal frequency,
_{4, then} the phase φ ₃ φ is also the same numerical value.

Next, a temporary resonance frequency f _r1 and a temporary resonance frequency f _a1 are derived from the following relational expressions (1) and (2) using a function approximation method called an interpolation method. _{f r1 = f 1 + (Δf} S · φ 1) / (φ 2 -φ 1) ...... (1) f a1 = f 3 + (Δf S · φ 3) / (φ 3 -φ 4) ...... ( 2) (However, f ₁ <f ₂ <f ₃ <f ₄ , φ ₂ >0> φ ₁ , φ ₃ >)
0> φ ₄ ) Next, as shown in FIG. 3, the phases φ ₅ and φ ₆ of the piezoelectric ceramic vibrator at the provisional resonance frequency _{fr 1} and the provisional anti-resonance frequency f _a1 are measured. If the phases φ ₅ and φ ₆ are within the predetermined phase tolerance, the provisional resonance frequency _{fr 1} and the provisional anti-resonance frequency f _a1 are changed to the resonance frequency (measured value) and the anti-resonance frequency ( Measured value)
Each measured impedance at these frequencies f _r1, f _a1 seek resonance impedance Z _r and the anti-resonance impedance Z _a.

On the other hand, the phase φ_FiveOr φ₆At least one of
If one of them is out of the predetermined phase tolerance, further use the interpolation method.
Repeat the above process until a phase within the tolerance is obtained
You. For example, the temporary resonance frequency f_r1Phase at_FiveIs given
Out of phase tolerance and φ_FiveIf> 0,
As shown in FIG. 4, the temporary resonance frequency f_r1Starting from
Frequency pitch Δf_SFrequency pitch Δf less than half of_S2
The phase characteristics of the piezoelectric ceramic
Sample. In the present embodiment, Δf_S2= (Δf _S/
2). Then, before passing through phase 0 ° for the first time,
Sampling frequency f_FiveAnd its phase φ₇Measure and rank first
Sampling frequency f after passing through phase 0 °₆And that place
Phase φ₈Is measured. However, in this embodiment,
Frequency f_FiveIs the temporary resonance frequency f_r1And the phase φ_FiveAnd φ
₇Also have the same numerical value.

Next, using the interpolation method, a temporary resonance frequency _fr2 is derived again from the following relational expression (3). _{fr 2} = f ₆ + (Δf _S2 · φ ₈ ) / (φ ₅ -φ ₈ ) (3) Next, the phase φ ₉ of the piezoelectric ceramic vibrator at the provisional resonance frequency _{fr 2} is measured. Then, if the phase phi ₉ is within a predetermined phase tolerance, the resonance frequency f _r2 provisional with the resonance frequency of the piezoelectric ceramic vibrator (measured value), measures the impedance at the frequency f _r2 by resonance determine the impedance Z _r.

According to the above method, sampling is performed at a smaller frequency pitch as the frequency approaches the phase 0 ° (ie, the resonance frequency and the antiresonance frequency). Irrespective of whether or not the unnecessary frequency is sampled at a constant frequency pitch, the impedance characteristic can be measured without waste and with high accuracy as compared with the conventional method.

The method for measuring the impedance characteristic of a piezoelectric component according to the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the gist.

[0017]

As apparent from the above description, according to the present invention, as the frequency approaches the phase 0 °, that is, the resonance frequency and the anti-resonance frequency, sampling is performed at a smaller frequency pitch, and wastefulness is obtained. It is possible to quickly perform accurate and accurate measurement.

[Brief description of the drawings]

FIG. 1 is a graph illustrating impedance characteristics and phase characteristics of a piezoelectric component, for describing an embodiment of a method for measuring impedance characteristics of a piezoelectric component according to the present invention.

FIG. 2 is a graph for explaining a method for measuring impedance characteristics of a piezoelectric component having the characteristics shown in FIG.

FIG. 3 is a graph for explaining a method of measuring impedance characteristics following FIG. 2;

FIG. 4 is a graph illustrating a method of measuring impedance characteristics following FIG. 3;

[Explanation of symbols]

f _r ... resonant frequency f _a ... antiresonant frequency Delta] f _S ... frequency pitch _{f 1, f 2, f 3} , f 4 ... sampling frequency _{φ 1, φ 2, φ 3} , φ 4 ... phase f _r1 ... resonant frequency of temporary f _a1 : provisional anti-resonance frequency

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01H 15/00 G01R 27/02 G01R 29/22 H03H 3/02

Claims (3)

(57) [Claims] 1. A frequency range including a frequency at which a phase of a piezoelectric component becomes 0 ° at a predetermined frequency pitch Δf _S is sampled, and a sampling frequency f ₁ before passing through a phase of 0 ° is sampled.
And its phase phi _1, the phase 0゜Wo measuring a sampling frequency f ₂ and the phase phi ₂ after passing the temporary resonant frequency f _r1 and the temporary antiresonance frequency f _a1 noise
Re or one of the frequency, in relation f _r1 or _{f a1 = f 1 + (Δf} S · φ 1) / (φ 1 -φ 2) a step of deriving with the resonance of the temporary frequency f _r1 Phase of piezoelectric component φ5 or
Measures the phase φ6 of the piezoelectric component at the temporary anti-resonance frequency f _a1
And the phase φ5 or φ6 is within a predetermined phase tolerance.
The provisional resonance frequency _fr1 or the provisional anti-resonance frequency
measuring the impedance of the piezoelectric component at f _a1 , and measuring the impedance characteristic of the piezoelectric component. In 2. A piezoelectric component of the resonance frequency f _r and the anti-resonance frequency f slightly smaller frequency pitch than the difference Delta] f of _a Delta] f _S, successively the frequency region including the frequency of the piezoelectric component of the phase becomes 0 ° from the low-frequency side Sampling and sampling frequency f ₁ and its phase φ ₁ before first passing through phase 0 °, sampling frequency f ₂ and its phase φ ₂ after first passing through phase 0 °, and phase 0 ° again Measuring the sampling frequency f ₃ and its phase φ ₃ before passing through, and the sampling frequency f ₄ and its phase φ ₄ after passing through the phase 0 ° again; a temporary resonance frequency _{fr 1} and a temporary anti-resonance The frequency f _a1 is _expressed by a relational expression _{fr 1} = f ₁ + (Δf _S · φ ₁ ) / (φ ₂ -φ ₁ ) f _a1 = f ₃ + (Δf _S · φ ₃ ) / (φ ₃ -φ ₄ ) And the phase of the piezoelectric component at the provisional resonance frequency _fr1. φ5 and above
Measure the phase φ6 of the piezoelectric component at the temporary anti-resonance frequency f _a1
A step of, when said phase .phi.5 .phi.6 is within a predetermined phase tolerance, that and a step of measuring the impedance of the piezoelectric component in the provisional resonance frequency f _r1 and the temporary anti-resonance frequency f _a1 Characteristic impedance characteristic measuring method for piezoelectric components. 3. At least one of the phase φ5 and the phase φ6
If either phase is out of the specified tolerance,
Until the phase within the tolerance is obtained using interpolation.
3. The method according to claim 1, wherein each step is repeated.
3. The method for measuring impedance characteristics of a piezoelectric component according to claim 1.