JP2008205764A - Frequency adjustment apparatus of quartz vibrator, and frequency adjustment method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frequency adjustment apparatus of a quartz vibrator by which fine adjustment of frequency can be performed without exchanging load capacity. <P>SOLUTION: The frequency adjustment apparatus of a quartz vibrator includes an adjustment chamber in which a plurality of the quartz vibrators are housed, a plurality of oscillating circuits where the plurality of quartz vibrators are connected each other via cables, a switching circuit which switches selectively oscillating outputs of the oscillating circuits, a frequency measuring means which takes in the outputs of the oscillating circuits to measure a series resonant frequency without loading Fr bearing a definite relation to a series resonant frequency in loading FL, a control means which presets a given frequency range containing the target frequency Fr* to take in the outputs of the frequency measuring means and instructs a processing of a frequency fine adjustment region of the quartz vibrator to be adjusted so that the measured series resonant frequency without loading Fr of the quartz vibrator to be adjusted falls within the given frequency range containing the target frequency Fr*, and a processing means which processes the quartz vibrator to be regulated based on a control output of the control means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crystal resonator frequency adjusting apparatus and a crystal resonator frequency adjusting method, and in particular, a so-called fine adjustment that finally adjusts a frequency in a tuning fork type crystal resonator assembly process (series resonance frequency under load). The present invention relates to a crystal resonator frequency adjusting device and a crystal resonator frequency adjusting method used for frequency adjustment of a crystal resonator in a process.

  The crystal resonator has a structure in which a vibrating body is sealed in a holding container, and is expressed by an equivalent circuit shown in FIG. 14 in a state where it vibrates at a frequency near the resonance frequency. In the figure, R1 is an equivalent series resistance, C1 is an equivalent series capacitance, L1 is an equivalent series inductance, C0 is an equivalent series resistance R1, an equivalent series capacitance C1, and an equivalent series inductance L1 connected in parallel to each other. It is the combined capacity of the capacity and the capacity of the cage.

Here, the load capacity of the crystal unit will be briefly described. When operating the crystal resonator, it is connected to an oscillation circuit. FIG. 15 shows an equivalent state where the crystal resonator is connected to the oscillation circuit. That is, as shown in FIG. 15, the oscillation circuit side viewed from the crystal resonator X1 side can be expressed by a series circuit of an equivalent input capacitance Ci and an equivalent input resistance -Ri.
The crystal resonator X1 side can be equivalently expressed by a series circuit of an effective inductance Le and an effective resistance Re. The diagram shown on the left side of FIG. 15 and the diagram shown on the right side are equivalent, the equivalent input resistance -Ri is a negative resistance, the equivalent input capacitance Ci is a load capacitance, and this is denoted as CL. . That is, the load capacitance CL is an effective external capacitance when an oscillation circuit using a crystal resonator is viewed from the crystal resonator.

  The final adjustment (so-called fine adjustment) of the frequency of the conventional crystal unit is performed by connecting the resonator element to the holder and then press-fitting the cap into the holder in the assembly process of the crystal unit. It is commonly used.

FIG. 16 shows the configuration of a conventional frequency adjustment device for a crystal resonator. In the figure, the frequency adjusting device of the peripheral crystal resonator is an adjustment chamber (vacuum chamber) in which the chambers in which the crystal resonators 101-1, 101-2,. 100 and a plurality of crystal resonators 101-1, 101-2,..., 101-n are connected outside the adjustment chamber 100 via cables 150-1, 150-2,. a plurality of oscillation circuits 111-1 and 111-2, ..., 111-n is integrated measuring board 110 _1, 110 _2, ..., and 110 _n, the measurement substrate 110 _1, 110 _2, ..., output from 110 _n , 121-n having a switch 121-1, 121-2,..., 121-n for selectively outputting the oscillation circuit output and the oscillation circuit output output from the switching circuit 120, and measuring the oscillation frequency. And a frequency counter 130 for.

  One end of each of the plurality of crystal resonators 101-1, 101-2,..., 101-n and one input end of each of the corresponding plurality of oscillation circuits 111-1, 111-2,. Load capacitances CL1, CL2,..., CLn are connected to each other. These load capacities CL1, CL2,..., CLn are accommodated in the adjustment chamber 100.

In the above configuration, the oscillation circuit 111-1 to 111 -n having the load capacitance CLi (i = 1 to n) is oscillated in the vacuum adjustment chamber 100, and the oscillation output of each oscillation circuit is generated by the switching circuit 120. The oscillation frequency is measured by the frequency counter 130. While the oscillation frequency is monitored by the frequency counter 130, the weight of the fine adjustment region of the crystal unit to be adjusted accommodated in the adjustment chamber is evaporated by the laser, and the oscillation frequency (series resonance frequency FL during load) is set as the target. The frequency is adjusted (Patent Documents 1 and 2).
JP 2003-60470 A JP 2003-133879 A

  However, since the load capacity connected to the crystal unit corresponding to each of a large number of oscillation circuits differs for each customer, the load accommodated in the adjustment chamber while being connected to the crystal unit at the time of frequency adjustment There was a problem that it took time and effort to change the capacity, and the quartz crystal could not be efficiently produced.

  The present invention has been made in view of such circumstances, and provides a crystal resonator frequency adjusting device and a crystal resonator frequency adjusting method capable of finely adjusting the frequency without exchanging the load capacity. The purpose is to provide.

  In order to achieve the above object, the crystal resonator frequency adjusting device of the present invention includes an adjustment chamber in which a plurality of crystal resonators to be adjusted are accommodated, and a plurality of crystal resonators, each via a cable. A plurality of connected oscillation circuits, a switching circuit that captures and selectively outputs oscillation outputs of the plurality of oscillation circuits, and an oscillation circuit output that is output from the switching circuit, and a series resonance frequency (FL) under load Measuring means for measuring a no-load series resonance frequency (Fr) having a fixed relationship with the load, and a target frequency Fr of the no-load series resonance frequency (Fr) having a fixed relationship with the load-time series resonance frequency (FL). A predetermined frequency range including * is set in advance, the output of the frequency measuring means is taken in, and the measured series resonance frequency (Fr) at the time of no load of the crystal resonator to be adjusted includes the target frequency Fr * Control means for instructing processing of the frequency fine adjustment region of the crystal unit to be adjusted so as to be within a predetermined frequency range, and processing for processing the crystal unit to be adjusted based on the control output of the control unit Means.

In the crystal resonator frequency adjusting device of the present invention having the above-described configuration, each of the plurality of crystal resonators to be adjusted accommodated in the adjustment chamber is connected to each of the corresponding plurality of oscillation circuits, and these oscillations The output of the circuit is selectively output by the switching circuit, and the no-load series resonance frequency (Fr) having a fixed relationship with the on-load series resonance frequency (FL) is measured by the frequency measuring means from these oscillation outputs.
A predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with the on-load series resonance frequency (FL) is set in advance by the control means, and is output to the output of the frequency measurement means. Based on the frequency fine tuning region of the crystal resonator to be adjusted, the series resonance frequency (Fr) at the time of no load of the crystal resonator to be adjusted measured based on the frequency is within a predetermined frequency range including the target frequency Fr *. Processing is instructed, and the crystal unit to be adjusted is processed by the processing unit based on the control output of the control unit.
This makes it possible to finely adjust the on-load series resonance frequency without exchanging the load capacity as in the conventional case, and enables efficient production of the crystal resonator.

  In the crystal resonator frequency adjusting apparatus according to the present invention, the control means uses a plurality of crystal resonator samples as a measurement target, the no-load series resonance frequency (Fr) of the plurality of crystal resonators, and the crystal resonator. The parallel capacitance C0, which is the combined capacitance of the interelectrode capacitance and the capacitance of the cage, is measured, and a reference load capacitance CLn is connected to the plurality of crystal resonators, and the series resonance frequency (when loaded) of each crystal resonator FL), and the following equation

により前記複数の水晶振動子の各々について直列等価容量Ｃ１を算出し、該算出された直列等価容量Ｃ１と、上記測定された並列容量Ｃ０とから、水晶振動子の直列等価容量Ｃ１、並列容量Ｃ０の平均値Ｃ０（ａ），Ｃ１（ａ）を算出し、該算出された平均値Ｃ０（ａ），Ｃ１（ａ）と、所望の負荷容量ＣＬ＊を接続したときに測定して得られる負荷時直列共振周波数（ＦＬ）から前記目標周波数Ｆｒ＊を次式

The series equivalent capacitance C1 is calculated for each of the plurality of crystal resonators, and the series equivalent capacitance C1 and the parallel capacitance C0 of the crystal resonator are calculated from the calculated series equivalent capacitance C1 and the measured parallel capacitance C0. The average value C0 (a), C1 (a) is calculated, and the load obtained by measuring the calculated average value C0 (a), C1 (a) and the desired load capacity CL * is obtained. The target frequency Fr * is calculated from the time series resonance frequency (FL) as follows:

により算出することを特徴とする。

It is characterized by calculating by.

  In the crystal resonator frequency adjusting device of the present invention having the above-described configuration, a plurality of crystal resonator samples are subjected to measurement, the no-load series resonance frequency (Fr) of the plurality of crystal resonators, and between the electrodes of the crystal resonator A parallel capacitance C0, which is a combined capacitance of the capacitance and the capacitance of the cage, is measured, and a reference load capacitance CLn is connected to the plurality of crystal resonators, and the series resonance frequency (FL) at the time of loading of each crystal resonator is determined. As well as measuring,

により前記複数の水晶振動子の各々について直列等価容量Ｃ１を算出し、該算出された直列等価容量Ｃ１と、上記測定された並列容量Ｃ０とから、水晶振動子の直列等価容量Ｃ１、並列容量Ｃ０の平均値Ｃ０（ａ），Ｃ１（ａ）を算出し、該算出された平均値Ｃ０（ａ），Ｃ１（ａ）と、所望の負荷容量ＣＬ＊を接続したときに測定して得られる負荷時直列共振周波数（ＦＬ）から前記目標周波数Ｆｒ＊を次式

The series equivalent capacitance C1 is calculated for each of the plurality of crystal resonators, and the series equivalent capacitance C1 and the parallel capacitance C0 of the crystal resonator are calculated from the calculated series equivalent capacitance C1 and the measured parallel capacitance C0. The average value C0 (a), C1 (a) is calculated, and the load obtained by measuring the calculated average value C0 (a), C1 (a) and the desired load capacity CL * is obtained. The target frequency Fr * is calculated from the time series resonance frequency (FL) as follows:

により算出する.
これにより、所望の負荷容量を水晶振動子に接続した際の無負荷時直列共振周波数（目標周波数）Ｆｒ＊を算出することにより、水晶振動子の周波数調整範囲である、負荷時直列共振周波数（ＦＬ）と一定の関係にある無負荷時直列共振周波数（Ｆｒ）の目標周波数Ｆｒ＊を含む所定の周波数範囲を予め設定することができる。

Calculated by
Thus, by calculating the no-load series resonance frequency (target frequency) Fr * when a desired load capacity is connected to the crystal resonator, the load series resonance frequency (the frequency adjustment range of the crystal resonator ( A predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with (FL) can be set in advance.

In addition, according to the frequency adjustment method of the crystal resonator of the present invention, the plurality of crystal resonators to be adjusted respectively capture the oscillation outputs of the plurality of oscillation circuits connected via the cables, and are selectively selected by the switching circuit. A first step of outputting;
A second step of taking an oscillation circuit output outputted from the switching circuit and measuring a no-load series resonance frequency (Fr) having a fixed relationship with a load series resonance frequency (FL) by a frequency measuring means;
A predetermined frequency range including a target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with the load series resonance frequency (FL) is preset by the control means, and the output of the frequency measurement means Frequency adjustment region of the crystal resonator to be adjusted so that the no-load series resonance frequency (Fr) of the crystal resonator to be adjusted is within a predetermined frequency range including the target frequency Fr *. A third step for instructing the processing of
A fourth step of processing the crystal resonator to be adjusted by a processing unit based on a control output of the control unit;
It is characterized by having.

In the crystal resonator frequency adjustment method of the present invention comprising the above steps, a plurality of crystal resonators to be adjusted receive the oscillation outputs of a plurality of oscillation circuits connected via cables, respectively, and are switched by a switching circuit. Output selectively.
Further, the oscillation circuit output outputted from the switching circuit is taken in, and the no-load series resonance frequency (Fr) having a fixed relationship with the on-load series resonance frequency (FL) is measured by the frequency measuring means.
The control means presets a predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with the load-time series resonance frequency (FL). The frequency of the crystal resonator to be adjusted is adjusted so that the no-load series resonance frequency (Fr) of the crystal resonator to be adjusted is within a predetermined frequency range including the target frequency Fr *. Processing of the fine adjustment area is instructed, and the processing means processes the crystal resonator to be adjusted based on the control output of the control means.
This makes it possible to finely adjust the on-load series resonance frequency without exchanging the load capacity as in the conventional case, and enables efficient production of the crystal resonator.

Further, the frequency adjustment method for a crystal resonator according to the present invention includes a plurality of crystal resonator samples as a measurement target, a no-load series resonance frequency (Fr) of the plurality of crystal resonators, and an interelectrode capacitance of the crystal resonator. A fifth step of measuring a parallel capacity C0, which is a combined capacity with the capacity of the cage;
A sixth step of connecting a reference load capacitance CLn to the plurality of crystal resonators and measuring a series resonance frequency (FL) under load of each crystal resonator;
From the measurement results in the fifth and sixth steps,

により前記複数の水晶振動子の各々について直列等価容量Ｃ１を算出する第７のステップと、
前記第７のステップにおいて算出された直列等価容量Ｃ１と、前記第５のステップにおいて測定された並列容量Ｃ０とから、水晶振動子の直列等価容量Ｃ１、並列容量Ｃ０の平均値Ｃ０（ａ），Ｃ１（ａ）を算出する第８のステップと、
前記第８のステップで算出された平均値Ｃ０（ａ），Ｃ１（ａ）と、所望の負荷容量ＣＬ＊を接続したときに測定して得られる負荷時直列共振周波数（ＦＬ）とから前記目標周波数Ｆｒ＊を次式

A seventh step of calculating a series equivalent capacitance C1 for each of the plurality of crystal resonators by:
From the series equivalent capacitance C1 calculated in the seventh step and the parallel capacitance C0 measured in the fifth step, an average value C0 (a) of the series equivalent capacitance C1 and the parallel capacitance C0 of the crystal resonator, An eighth step of calculating C1 (a);
From the average values C0 (a) and C1 (a) calculated in the eighth step and a load series resonance frequency (FL) obtained by measurement when a desired load capacitance CL * is connected, the target The frequency Fr * is

により算出する第９のステップと、
を有することを特徴とする。

A ninth step of calculating by:
It is characterized by having.

  In the crystal resonator frequency adjustment method of the present invention comprising the above steps, a plurality of crystal resonator samples are measured, and the series resonance frequency (Fr) of the plurality of crystal resonators at no load and between the electrodes of the crystal resonator are measured. A parallel capacitance C0, which is a combined capacitance of the capacitance and the capacitance of the cage, is measured, and a reference load capacitance CLn is connected to the plurality of crystal resonators, and the series resonance frequency (FL) at the time of loading of each crystal resonator is determined. As well as measuring,

により前記複数の水晶振動子の各々について直列等価容量Ｃ１を算出し、該算出された直列等価容量Ｃ１と、上記測定された並列容量Ｃ０とから、水晶振動子の直列等価容量Ｃ１、並列容量Ｃ０の平均値Ｃ０（ａ），Ｃ１（ａ）を算出し、該算出された平均値Ｃ０（ａ），Ｃ１（ａ）と、所望の負荷容量ＣＬ＊を接続したときに測定して得られる負荷時直列共振周波数（ＦＬ）から前記目標周波数Ｆｒ＊を次式

The series equivalent capacitance C1 is calculated for each of the plurality of crystal resonators, and the series equivalent capacitance C1 and the parallel capacitance C0 of the crystal resonator are calculated from the calculated series equivalent capacitance C1 and the measured parallel capacitance C0. The average value C0 (a), C1 (a) is calculated, and the load obtained by measuring the calculated average value C0 (a), C1 (a) and the desired load capacity CL * is obtained. The target frequency Fr * is calculated from the time series resonance frequency (FL) as follows:

により算出する。
これにより、所望の負荷容量を水晶振動子に接続した際の無負荷時直列共振周波数（目標周波数）Ｆｒ＊を算出することにより、水晶振動子の周波数調整範囲である、負荷時直列共振周波数（ＦＬ）と一定の関係にある無負荷時直列共振周波数（Ｆｒ）の目標周波数Ｆｒ＊を含む所定の周波数範囲を予め設定することができる。

Calculated by
Thus, by calculating the no-load series resonance frequency (target frequency) Fr * when a desired load capacity is connected to the crystal resonator, the load series resonance frequency (the frequency adjustment range of the crystal resonator ( A predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with (FL) can be set in advance.

  As described above, according to the present invention, a predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) that has a certain relationship with the load series resonance frequency (FL) is set in advance. Then, the frequency fine adjustment region of the crystal unit to be adjusted is processed so that the no-load series resonance frequency (Fr) of the crystal unit to be adjusted falls within a predetermined frequency range including the target frequency Fr *. As a result, the series resonance frequency under load can be finely adjusted without exchanging the load capacity as in the prior art, and the crystal resonator can be efficiently produced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the configuration of a crystal resonator frequency adjusting device according to an embodiment of the present invention. In the figure, the frequency adjustment device for the crystal resonator according to the embodiment of the present invention is such that the chamber in which the crystal resonators 10-1, 10-2,. The adjustment chamber (vacuum chamber) 1 and the plurality of crystal resonators 10-1, 10-2,..., 10-n are respectively connected to the cables 50-1, 50-2,. , 2n, and measurement boards 2 ₁ , 2 ₂ ,..., 20- _n, and the measurement boards 2 ₁ , 2 ₂ ,. 2, the switching circuit 3 having switches 30-1, 30-2,..., 30 -n that take in and selectively output the oscillation circuit output output from 2 _n , and the oscillation circuit output output from the switching circuit 3 Capture and measure the oscillation frequency of each oscillation circuit 20-1, 20-2, ..., 20-n And the wave number counter 4, and a processing unit 5 for processing for adjusting the frequency of the crystal oscillator, and a control unit 6 that controls each unit.

The switching circuit 3 includes switches 30-1, 30-2,..., 30-n, and the outputs of the oscillation circuits 20-1, 20-2,. The frequency counter 4 is sequentially fetched in a time division manner.
The processing apparatus 5 is, for example, a laser processing apparatus, and, for example, a YAG laser is used as a laser type of a laser oscillator constituting the laser processing apparatus.

  As shown in FIG. 2, the processing device 5 irradiates a frequency fine adjustment region 201 of a crystal resonator 200 housed in a ceramic package with a laser beam 210 emitted from a laser oscillator (not shown). The weight formed on 201 is partially evaporated. This adjusts the frequency of the series resonance frequency of the crystal resonator.

  Moreover, the processing apparatus 5 can use the ion irradiation apparatus which irradiates ions, such as argon, as means other than a laser processing apparatus, for example. For example, as shown in FIG. 3, an ion flow 310 such as argon is irradiated on one side of a crystal resonator 300 housed in a ceramic package to a window 301 having a window open, and the frequency fine adjustment region 301 is thinned to adjust the frequency. Do. FIG. 3A is an explanatory diagram showing a state in which ions are radiated to a frequency fine adjustment region of a crystal resonator housed in a ceramic package, and FIG. 3B is an X− in FIG. It is sectional drawing by a X cut line.

    The control unit 6 presets a predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with the load-time series resonance frequency (FL), and outputs the output of the frequency counter 4. The no-load series resonance frequency (Fr) of the crystal resonators 10-1, 10-2,..., 10-n that have been captured and measured is within a predetermined frequency range including the target frequency Fr *. , 10-n of the crystal resonators 10-1, 10-2 to 10 -n to be adjusted. The frequency counter 4 corresponds to the frequency measuring means of the present invention, the processing device 5 corresponds to the processing means of the present invention, and the control unit 6 corresponds to the control means of the present invention.

  In the crystal resonator frequency adjusting device according to the embodiment of the present invention, one end of each of the plurality of crystal resonators 10-1, 10-2,..., 10-n and the corresponding plurality of oscillation circuits 20-1, No load capacitance is connected between one input terminal of each of 20-2,..., 20-n. That is, in the frequency adjustment device for a crystal resonator according to the embodiment of the present invention, the series resonance frequency (no-load series resonance frequency) in a state where no capacitive load is connected to the crystal resonator is measured, and the detected no-load time Adjustment is made so that the series resonance frequency falls within the adjustment range of the no-load series resonance frequency corresponding to the adjustment range of the desired load series resonance frequency.

  The operation of the crystal resonator frequency adjusting apparatus according to the embodiment of the present invention having the above-described configuration will be described with reference to the flowcharts shown in FIGS. FIG. 4 shows a process for obtaining in advance the value of the no-load series resonance frequency Fr * having a fixed relationship with the on-load series resonance frequency FL when a desired (necessary) load capacitance is connected to the crystal resonator. Yes.

In FIG. 4, first, the no-load series resonance frequency Fr of the crystal resonator and the parallel capacitance C0 in the equivalent circuit of the crystal resonator are measured (step 400).
Reference load capacitance (hereinafter referred to as reference load capacitance) CLn is set to CLn = 12.5 pF, and this reference load capacitance is connected to a crystal resonator in which a resonator element is connected to a wafer. After this adjustment, the case is press-fitted to complete the crystal unit. Next, the no-load series resonance frequency Fr and the parallel capacitance C0 are measured with respect to the completed plural (for example, k) crystal resonators S1, S2,.
In addition, since the parallel capacitance C0 includes a capacitance formed with the holding container, it is necessary to measure the crystal resonator with a completed body.

Next, an impedance analyzer is used to connect a reference load capacitance CLn = 12.5 pF with respect to the samples of the previous k crystal resonators S1, S2,... FL is measured (step 401).
Further, in step 402, the no-load series resonance frequency Fr of the crystal resonator obtained in steps 400 and 401, the parallel capacitance C0 in the equivalent circuit of the crystal resonator, and the load series resonance frequency FL are expressed by the following equation (9). As a result, the series equivalent capacitance C1 of the crystal resonator is calculated.

因みに、上式（９）の導出過程について説明する。既述した図１４に示す水晶振動子の等価回路において、直列共振回路の共振周波数ｆｒは、次式で表される。

Incidentally, the derivation process of the above equation (9) will be described. In the equivalent circuit of the crystal resonator shown in FIG. 14 described above, the resonance frequency fr of the series resonance circuit is expressed by the following equation.

また、図１４に示す水晶振動子の等価回路において、並列共振周波数ｆａは、次式で表される

In the equivalent circuit of the crystal unit shown in FIG. 14, the parallel resonance frequency fa is expressed by the following equation.

一方、負荷容量ＣＬを水晶振動子に接続した場合は、図５（Ａ）のようになる。しかし、実用的な範囲では、制御部６では、図５（Ｂ）に示すように負荷容量が水晶振動子に対し、並列接続されたものとして近似してもさしつかえないとされる。
したがって、式（１１）において、Ｃ０の代わりに、Ｃ０＋ＣＬで置き換えて式を変形すると、次式が得られる。

On the other hand, when the load capacitor CL is connected to a crystal resonator, the result is as shown in FIG. However, in a practical range, the control unit 6 can approximate the load capacitance as being connected in parallel to the crystal resonator as shown in FIG. 5B.
Accordingly, in the equation (11), when the equation is modified by replacing it with C0 + CL instead of C0, the following equation is obtained.

すなわち、式（９）が導出される。
上式（９）により、ｋ個の水晶振動子Ｓ１，Ｓ２，…，Ｓｋのサンプルの直列等価容量Ｃ１を算出する。このようにして得られたｋ個の並列容量Ｃ０及び直列等価容量Ｃ１の値から並列容量Ｃ０及び直列等価容量Ｃ１の平均値Ｃ０（ａ），Ｃ１（ａ）を算出する。

That is, Expression (9) is derived.
The series equivalent capacitance C1 of the samples of k crystal resonators S1, S2,..., Sk is calculated by the above equation (9). Average values C0 (a) and C1 (a) of the parallel capacitance C0 and the series equivalent capacitance C1 are calculated from the values of the k parallel capacitances C0 and the series equivalent capacitance C1 thus obtained.

Next, when no load is applied when the necessary load capacitance value CL * is connected from the parallel capacitance C0 calculated in step 402, the average values C0 (a) and C1 (a) of the series equivalent capacitance C1, and the series resonance frequency FL when loaded. A series resonance frequency Fr * is calculated (step 403). For example, when a load series resonance frequency FL when a load capacitance CL of 4 pF is connected to a crystal resonator is FL = 32768 Hz, the value of the no-load series resonance frequency Fr * is obtained from Equation (9). Specifically, when C1 (a) = 0.1978pF, C0 (a) = 0.857pF, and substitution into the equation (9), Fr * = 32761.33 (Hz).
Furthermore, the no-load series resonance frequency Fr * when another desired load capacitance CL * is connected to the crystal resonator can be obtained in the same manner. An example of the no-load series resonance frequency Fr * with respect to the desired load capacity CL * calculated in this way is shown in FIG. Data indicating the value of the no-load series resonance frequency Fr * for the desired load capacity CL * is stored as a table in the memory in the control unit 6 shown in FIG.

Under such a state, the control unit 6 sets a predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) that is in a fixed relation with the load series resonance frequency (FL) ( Step 500). That is, for example, the target frequency Fr * is set to Fr * ± 20 ppm in consideration of the tolerance.
Next, a predetermined number (K = n) of crystal resonators to be adjusted are set in the adjustment chamber 1, and the count value K of the counter K that counts the number of crystal resonators is set to K = 1 (step 501). ).

  Further, in step 502, the no-load series resonance frequency Fr of the sample of the Kth crystal resonator is measured by the frequency counter 4, and the measured no-load series resonance frequency Fr is the target of the no-load series resonance frequency Fr. Until the predetermined frequency range including the frequency Fr * is reached, the processing device 5 continues to process the fine frequency adjustment region of the crystal resonator to be adjusted under the control of the control unit 6 (step 503).

  Next, it is determined whether or not the no-load series resonance frequency Fr of the crystal unit to be adjusted measured by the frequency counter 4 falls within a predetermined frequency range including the target frequency Fr * (step 504). ). If the determination in step 504 is negative, the process returns to step 503, and the processing apparatus 5 continues the processing of the frequency fine adjustment region of the crystal resonator to be adjusted.

  If the determination in step 504 is affirmative, the count value K of the counter K that counts the number of crystal resonators is incremented by +1 (step 505), and a predetermined number (K = n) of crystal resonator samples are counted. It is determined whether or not the processing is finished, that is, whether or not the frequency adjustment is finished (step 506). If the determination in step 506 is negative, the process returns to step 502, and the processes described in steps 502 to 505 are repeated. If the determination in step 506 is affirmative, that is, if it is determined that the frequency adjustment of a predetermined number (K = n) of crystal resonator samples has been completed, this processing ends.

When the above process is performed for each of a plurality of desired (necessary) load capacitances CL * (for example, CL * = 3 pF, 4 pF, 6 pF, 7.5 pF, 12.5 pF, 20 pF). In each of these, a predetermined frequency range including the target frequency Fr * corresponding to each load capacitance CL * is set and executed, thereby indirectly performing fine adjustment of the on-load series resonance frequency of the crystal resonator. be able to.
In other words, the series resonance frequency of the crystal resonator used by connecting the desired load capacitance CL * can be finely adjusted without connecting the load capacitance, and the efficiency of the crystal resonator can be adjusted. Production becomes possible.

In the prior art, it is necessary to exchange the load capacitance connected to the crystal unit in the adjustment chamber every time the capacitance value of the desired load capacitance CL * is changed. In the actual fine adjustment of the series resonance frequency when the crystal unit is loaded, dozens of crystal units are accommodated in the adjustment chamber, and the frequency is adjusted by time division processing. It is necessary to prepare the load capacity as many as the number of crystal units. Since these numbers of load capacities are exchanged each time the capacity value of the load capacities is changed, it is very inefficient.
In the present invention, the control executed by the control unit 6 by calculating in advance the target frequency Fr * of the no-load series resonance frequency having a fixed relationship with the on-load series resonance frequency by the processing shown in FIG. By inputting only the target value of the program (target frequency Fr * of the no-load series resonance frequency), it is possible to finely adjust the frequency of the series resonance frequency when the crystal resonator is loaded.

The frequency adjustment device according to the embodiment of the present invention finely adjusts the frequency finally, and a completed crystal resonator sample is connected to CL * = 4 pF as an example of a desired load capacitance CL * to be a network analyzer. FIG. 8 shows the result of measuring the on-load series resonance frequency FL. FIG. 8 is a diagram showing a distribution obtained by measuring a series resonance frequency FL under load for a plurality of crystal resonator samples and obtaining a deviation from 32.768 KHz. The standard deviation of the load series resonance frequency FL is within ± 20 ppm for all samples, and the load series resonance frequency FL varies greatly even in the case of such a small load capacity. Needed without.
In the above-described embodiment, the example in which the oscillation circuit is installed outside the adjustment chamber has been described. However, it is obvious that the oscillation circuit may be installed in the adjustment chamber.

  The effect of the present invention will be further examined. In the present invention, the no-load series resonance frequency Fr of the crystal resonator is measured, and the frequency adjustment is performed so that the measured value falls within the required range. The characteristics of the vibrator are premised on being processed within a certain range.

  That is, it is assumed that the values of the equivalent series capacitance C1 and the parallel capacitance C0 measured in the case of a finished product do not vary greatly when manufactured in accordance with the working standard of the determined process. . Even if the values of the equivalent series capacitance C1 and the parallel capacitance C0 are greatly different, it is very small, and it is caused by a process abnormality or a work mistake, which greatly affects the manufacturing yield. Not to do.

  FIG. 9 shows the average value and standard deviation of the equivalent series capacitance C1, the parallel capacitance C0, and the capacitance ratio C0 / C1 (= γ) of various crystal resonator samples depending on the value of the series resonance frequency FL under load and the difference in appearance. (Abbreviated as deviation in the figure). In the figure, (a) to (e) are 1.2 mm cylinder package type tuning fork type crystal resonators. Each of (a) to (d) has a different oscillation frequency. The length of the tuning fork arm is different, and the length of the vibrating arm is shortened as the oscillation frequency is increased, and the values of the parallel capacitance C0 and the equivalent series capacitance C1 are also decreased. The value of the capacity ratio γ itself is increasing.

  The crystal resonator of (e) is a surface mount type crystal resonator in which the crystal resonator of the cylinder type package of (a) is molded with epoxy resin. It has a structure in which the outer lead portion of the original cylinder type package is further connected to a lead frame that forms an external electrode terminal, and the values of the parallel capacitance C0 and the equivalent series capacitance C1 are compared with the crystal resonator of FIG. However, the value of the capacitance ratio γ does not change so much, and the standard deviation itself is the same as in the case of the crystal resonator of FIG.

9F is an example of a 2 mm cylinder package type tuning fork type crystal resonator. Unlike the crystal resonators of FIGS. 9A to 9E, the external dimensions of the resonator element are intentionally different. Is produced with poor accuracy, and the standard deviation of the values of the parallel capacitance C0 and the equivalent series capacitance C1 is large. As is clear from FIG. 9, the standard deviation of the values of the parallel capacitor C0 and the equivalent series capacitor C1 is 10 times or more as compared with the crystal resonator of FIG. Also, the standard deviation of the capacity ratio γ is large.
Incidentally, as described above, the relationship between the series resonance frequency FL when loaded and the series resonance frequency Fr when no load is expressed by the following equation.

ここで負荷時直列共振周波数ＦＬと無負荷時直列共振周波数Ｆｒとの差を無負荷時直列共振周波数Ｆｒで除した値（以下、負荷時周波数オフセット量と記す。）ＤＬを導入して、等価定数（Ｃ０、Ｃ１）との関係を考察する。Ｃ１≪Ｃ０＋ＣＬとすると、負荷時周波数オフセット量ＤＬは、

Here, a value obtained by dividing the difference between the series resonance frequency Fr when loaded and the series resonance frequency Fr when no load is divided by the series resonance frequency Fr when no load is applied (hereinafter referred to as a frequency offset amount when loaded) DL is introduced to obtain an equivalent. Consider the relationship with constants (C0, C1). When C1 << C0 + CL, the load frequency offset amount DL is

となる。上式（１４）は、ある特定の並列容量Ｃ０及び等価直列容量Ｃ１を有する１つの水晶振動子の負荷容量に対する関係を示す式であり、負荷時周波数オフセット量ＤＬの負荷容量ＣＬ依存性を示している。この負荷時周波数オフセット量ＤＬの負荷容量ＣＬ依存性を示す特性曲線は、ＣＬ曲線と呼ばれ、模式的に図１０に示す。式（１４）において、負荷容量ＣＬが無限大に大きくなるときは、右辺の分母は無限大になり、従って、右辺は０に近づく。このときは、ＤＬ＝０である。
一方、負荷容量ＣＬが小さくなり、数ｐＦの値に近づくと、負荷時周波数オフセット量ＤＬの値は急激に増加して図１０に示す曲線を描くこととなる。

It becomes. The above equation (14) is an equation showing the relationship with respect to the load capacitance of one crystal resonator having a specific parallel capacitance C0 and equivalent series capacitance C1, and shows the load capacitance CL dependence of the load frequency offset amount DL. ing. A characteristic curve indicating the dependency of the load frequency offset amount DL on the load capacitance CL is called a CL curve, and is schematically shown in FIG. In the equation (14), when the load capacity CL increases to infinity, the denominator on the right side becomes infinity, and therefore the right side approaches 0. At this time, DL = 0.
On the other hand, when the load capacitance CL decreases and approaches a value of several pF, the value of the on-load frequency offset amount DL increases rapidly and draws a curve shown in FIG.

  FIG. 11 roughly shows the relationship between the load frequency offset amount DL, the equivalent constant, and the load capacitance CL. FIG. 11 shows the range (width) of the load frequency offset amount DL when the load capacitance CL is 4 pF and 20 pF in the crystal resonator having the equivalent constant shown in FIG. Yes. When the range of the frequency offset amount DL at the time of loading is narrow, it indicates that the frequency of the crystal resonator finely adjusted by the frequency adjusting device (or frequency adjusting method) according to the present invention is distributed in a narrow range, and conversely the load When the range of the value of the hourly frequency offset amount DL is wide, it indicates that the oscillation frequency of the completed crystal resonator varies widely.

  In FIG. 11, the parallel capacitor C0 adopts an average value for rough estimation, and the value of the capacity ratio γ is obtained by adding the value of three times the standard deviation to the average value of the capacity ratio γ, Subtracted values, that is, (average value of capacity ratio γ + 3σ) and (average value of capacity ratio γ−3σ) were employed. The maximum value of the load frequency offset amount DL is when the capacity ratio γ is (average value of the capacity ratio γ−3σ), and the minimum value of the load frequency offset amount DL is the capacity ratio γ (the average value of the capacity ratio γ). + 3σ).

  As shown in FIG. 11, when the load capacitance CL is large (CL = 20 pF), the range of the load frequency offset amount DL is small. Therefore, it is shown that the range of frequency variation can be sufficiently reduced by fine adjustment of the series resonance frequency of the crystal resonator by the frequency adjusting device (or frequency adjusting method) of the present invention.

  However, as a result of intentionally making the accuracy worse, in the case of the crystal resonator of (f) having a large variation in equivalent constant, the range of the load frequency offset amount DL is large and is 18.6 ppm. . Therefore, when the finishing tolerance is set to ± 10 ppm, the yield is expected to decrease. In this case, a conventional method of adjusting the series resonance frequency by connecting a load capacitor has to be adopted.

When the load capacitance CL is a small value such as 4 pF, in the crystal resonators (a) to (e), the range of the load frequency offset amount DL is in the range of about 8 to 11 ppm. This means that the frequency variation range is larger than when the load capacitance CL is CL = 20 pF. However, when the tolerance is set to ± 20 ppm, it can be sufficiently adjusted within the setting range. Is shown.
The meaning of FIG. 11 described above is indicated by the CL curve as shown in FIGS. FIG. 12 is a CL curve in the case of the crystal resonator of (e), and FIG. 13 is a CL curve in the case of the crystal resonator of (f).

The block diagram which shows the structure of the frequency adjustment apparatus of the crystal oscillator which concerns on embodiment of this invention. Explanatory drawing which shows an example of the processing apparatus in the frequency adjustment apparatus of the crystal oscillator based on embodiment of this invention shown in FIG. Explanatory drawing which shows the other example of the processing apparatus in the frequency adjustment apparatus of the crystal oscillator based on embodiment of this invention shown in FIG. In the frequency adjusting apparatus for a crystal resonator according to the embodiment of the present invention shown in FIG. 1, a procedure for acquiring data of a target frequency value of a no-load resonance frequency stored in advance in a memory in a control unit necessary for frequency adjustment The flowchart which shows. The figure for demonstrating the derivation | leading-out process of the relational expression of the series resonance frequency at the time of load, and the series resonance frequency at the time of no load. The contents of the table showing the relationship between the capacity value of the desired load capacity to be connected to the crystal unit and the target frequency value of the no-load series resonance frequency corresponding to the crystal capacity obtained by the procedure shown in FIG. FIG. The flowchart which shows operation | movement of the frequency adjustment apparatus of the crystal oscillator based on embodiment of this invention shown in FIG. The figure which measured the on-series resonance frequency FL about the sample of several crystal oscillator, calculated | required the standard deviation from the average value of the measured value, and showed the distribution. The figure which shows the relationship between the average value and standard deviation of the equivalent series capacity | capacitance C1, the parallel capacity | capacitance C0, and the capacitance ratio C0 / C1 of the sample of various crystal oscillators by the difference in the value of the series resonance frequency FL at the time of load, and external appearance. The figure which showed typically the CL curve which shows the load capacity CL dependence of the frequency offset amount DL at the time of a crystal oscillator. FIG. 10 is a diagram showing a range (width) of a value of a load frequency offset amount DL when the load capacitance CL is 4 pF and 20 pF in the crystal resonator having the equivalent constant shown in FIG. 9. The figure which showed CL curve in the case of a specific crystal oscillator based on the data shown in FIG. The figure which showed CL curve in the case of another crystal resonator based on the data shown in FIG. The figure which shows the equivalent circuit of a crystal oscillator. Explanatory drawing which equivalently showed the state which connected the crystal oscillator to the oscillation circuit. The block diagram which shows the structure of the frequency adjustment apparatus of the conventional crystal oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Adjustment room 2 ₁ , 2 ₂ , ... 2 _n ... Measurement board 3 ... Switching circuit 4 ... Frequency counter 5 ... Processing device 6 ... Control part

Claims (4)

An adjustment chamber containing a plurality of crystal resonators to be adjusted; and
A plurality of crystal resonators each connected via a cable, a plurality of oscillation circuits;
A switching circuit for capturing and selectively outputting the oscillation outputs of the plurality of oscillation circuits;
A frequency measuring means for taking in an oscillation circuit output outputted from the switching circuit and measuring a no-load series resonance frequency (Fr) having a fixed relationship with a load series resonance frequency (FL);
A predetermined frequency range including the target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with the load series resonance frequency (FL) is set in advance, and the output of the frequency measuring means is taken in and measured. Instructing the processing of the fine frequency adjustment region of the crystal unit to be adjusted so that the no-load series resonance frequency (Fr) of the crystal unit to be adjusted falls within a predetermined frequency range including the target frequency Fr *. Control means;
Processing means for processing the crystal resonator to be adjusted based on the control output of the control means;
A frequency adjusting device for a crystal resonator, comprising: The control means includes
A parallel capacitance C0, which is a combined capacity of the no-load series resonance frequency (Fr) of the plurality of crystal resonators and the capacitance between the electrodes of the crystal resonator and the capacitance of the cage, is measured using samples of the plurality of crystal resonators. The reference load capacitance CLn is connected to the plurality of crystal resonators to measure the on-load series resonance frequency (FL) of each crystal resonator.

The series equivalent capacitance C1 is calculated for each of the plurality of crystal resonators, and the series equivalent capacitance C1 and the parallel capacitance C0 of the crystal resonator are calculated from the calculated series equivalent capacitance C1 and the measured parallel capacitance C0. The average value C0 (a), C1 (a) is calculated, and the load obtained by measuring the calculated average value C0 (a), C1 (a) and the desired load capacity CL * is obtained. The target frequency Fr * is calculated from the time series resonance frequency (FL) as follows:

The frequency adjustment device for a crystal resonator according to claim 1, wherein A first step in which a plurality of crystal resonators to be adjusted each receive an oscillation output of a plurality of oscillation circuits connected via a cable and selectively output by a switching circuit;
A second step of taking an oscillation circuit output outputted from the switching circuit and measuring a no-load series resonance frequency (Fr) having a fixed relationship with a load series resonance frequency (FL) by a frequency measuring means;
A predetermined frequency range including a target frequency Fr * of the no-load series resonance frequency (Fr) having a fixed relationship with the load series resonance frequency (FL) is preset by the control means, and the output of the frequency measurement means Frequency adjustment region of the crystal resonator to be adjusted so that the no-load series resonance frequency (Fr) of the crystal resonator to be adjusted is within a predetermined frequency range including the target frequency Fr *. A third step for instructing the processing of
A fourth step of processing the crystal resonator to be adjusted by a processing unit based on a control output of the control unit;
A method for adjusting the frequency of a crystal resonator, comprising: A parallel capacitance C0, which is a combined capacity of the no-load series resonance frequency (Fr) of the plurality of crystal resonators and the capacitance between the electrodes of the crystal resonator and the capacitance of the cage, is measured using samples of the plurality of crystal resonators. A fifth step of measuring;
A sixth step of connecting a reference load capacitance CLn to the plurality of crystal resonators and measuring a series resonance frequency (FL) under load of each crystal resonator;
From the measurement results in the fifth and sixth steps,

A seventh step of calculating a series equivalent capacitance C1 for each of the plurality of crystal resonators by:
From the series equivalent capacitance C1 calculated in the seventh step and the parallel capacitance C0 measured in the fifth step, an average value C0 (a) of the series equivalent capacitance C1 and the parallel capacitance C0 of the crystal resonator, An eighth step of calculating C1 (a);
From the average values C0 (a) and C1 (a) calculated in the eighth step and a load series resonance frequency (FL) obtained by measurement when a desired load capacitance CL * is connected, the target The frequency Fr * is

A ninth step of calculating by:
The frequency adjustment method for a crystal resonator according to claim 3, wherein:

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