JP2011172096A - Frequency adjustming device of piezoelectric vibrating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frequency adjustment device of a piezoelectric vibrating device with high quality and improved productivity. <P>SOLUTION: Frequency signals S2, S3 are transmitted from a frequency adjustment part to frequency counters 21, 22, respectively. As shown in a timing chart, operations for opening gates of the frequency counter circuits for a time 10ms based on a measurement starting signal, closing the gates and then transmitting measurement data to a control part 3 are repeated. The control part 3 receives the measurement data alternately from the frequency counter circuits 21, 22 and compares the measurement data with a preset frequency. On the stage where the measurement data become equal to or higher than the set frequency, the control part 3 transmits a control signal to the frequency adjustment part 1 to finish a frequency adjusting operation on a tuning fork type crystal vibrating element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a frequency adjusting device for a piezoelectric vibrating device such as a crystal resonator or a crystal oscillator used in an electronic apparatus.

  The piezoelectric vibration device is configured to obtain a specific frequency signal by forming a plurality of excitation electrodes made of a metal film on the surface of a piezoelectric diaphragm and applying an AC voltage to each excitation electrode. The piezoelectric vibrating device performs frequency adjustment by adding mass or decreasing mass to the piezoelectric vibrating plate in order to obtain a predetermined frequency. For example, in a tuning fork type crystal resonator, a metal film is formed on the tip region of the vibrating arm, and a metal material is additionally added to the metal film by partial vapor deposition, so that the frequency of the tuning fork type crystal resonator can be obtained. Was continuously reduced to adjust the frequency.

  Normally, the frequency adjustment status is monitored by measuring the current frequency with a frequency counter circuit, and if it has reached the desired frequency, the frequency adjustment is completed. It was.

JP 2007-43549 A

  By the way, frequency adjustment by mass addition such as partial vapor deposition is a method of continuously adding an additional substance such as a metal material, and the metal material which is an adjustment weight is also used in frequency adjustment by mass reduction such as ion milling. It is a technique that is continuously removed. In this way, the frequency adjustment mass is continuously adjusted. In contrast, frequency measurement by the frequency counter circuit requires a certain time. For this reason, even when the set (target) frequency is reached at the initial stage of the predetermined time, the frequency adjustment operation is continued until the end of the predetermined time. In this way, the target frequency may be greatly exceeded during a certain period of frequency measurement, resulting in a large frequency variation as a whole during mass production, leading to a reduction in quality.

  The present invention has been made to solve the above-described problems, and provides a frequency adjusting device for a piezoelectric vibration device that has excellent quality and improved productivity.

The present invention has been made in order to achieve the above object. As described in claim 1, the frequency adjustment of a piezoelectric vibration device that performs frequency adjustment by adding a mass for frequency adjustment to the piezoelectric vibration element. A device,
A frequency adjustment unit that adds mass for frequency adjustment to the piezoelectric vibration element, a plurality of frequency counter circuits that receive a frequency signal output from the frequency adjustment unit and measure a frequency for a predetermined time, and each frequency counter circuit A control unit that receives measurement data of the measured frequency, determines whether the received signal is equal to or lower than a set frequency, and transmits a frequency adjustment stop signal to the frequency adjustment device if the received signal is equal to or lower than a predetermined frequency; And the plurality of frequency counter circuits mutually shift a fixed time interval for measuring the frequency from the frequency adjusting unit, and after each frequency measurement for the fixed time, transmits measurement data to the control unit. This is a frequency adjustment device for a piezoelectric vibration device.

  According to the adjustment method, the plurality of frequency counter circuits shift a predetermined time interval for measuring the frequency from the frequency measurement unit, and transmit measurement data to the control unit after each measurement for the predetermined time. Since the method is employed, the measurement result of each frequency counter circuit can be transmitted to the control unit at a time interval that is half or less than half of the time. Since the control unit determines whether or not the received measurement data is equal to or lower than a predetermined frequency, it is possible to determine the frequency measurement result faster and more accurately than in the past.

According to a second aspect of the present invention, there is provided a frequency adjusting device for a piezoelectric vibrating device that performs frequency adjustment by reducing the frequency adjusting mass in the piezoelectric vibrating element,
A frequency adjustment unit that reduces the frequency adjustment mass in the piezoelectric vibration element, a plurality of frequency counter circuits that receive the frequency signal output from the frequency adjustment unit and measure the frequency for a predetermined time, and each frequency counter circuit A control unit that receives measurement data of the measured frequency, determines whether or not the received measurement data is equal to or higher than a predetermined frequency, and if it is equal to or higher than a predetermined frequency, a control unit that transmits a frequency adjustment stop signal to the frequency adjustment device; And the plurality of frequency counter circuits mutually shift a predetermined time interval for measuring the frequency from the frequency adjusting unit, and after each frequency measurement for the predetermined time, transmits measurement data to the control unit. The frequency adjusting device of the piezoelectric vibration device characterized by the above may be used.

  According to the adjustment method, the plurality of frequency counter circuits shift a predetermined time interval for measuring the frequency from the frequency measurement unit, and transmit measurement data to the control unit after each measurement for the predetermined time. Since the method is employed, the measurement result of each frequency counter circuit can be transmitted to the control unit at a time interval that is half or less than half of the time. Since the control unit determines whether or not the received measurement data is equal to or higher than a predetermined frequency, it is possible to determine the frequency measurement result faster and more accurately than in the past.

  According to the present invention, since it is possible to quickly and highly accurately determine the frequency measurement result, it is possible to obtain a frequency adjusting device for a piezoelectric vibrating device that is excellent in quality and improved in productivity.

The figure which shows the system configuration | structure in the frequency adjustment apparatus of the piezoelectric vibrating device which shows 1st Embodiment by this invention. The figure which shows the frequency adjustment part which shows 1st Embodiment by this invention. The figure which shows the timing chart by the system configuration | structure of FIG. Diagram showing frequency rise for frequency adjustment and time interval for frequency measurement The figure which shows distribution of the piezoelectric vibration device which frequency-adjusted by this invention The figure which shows the distribution of the piezoelectric vibration device which frequency adjusted by the conventional example

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
A first embodiment according to the present invention will be described with reference to FIGS. 1 to 5 by taking as an example a frequency adjusting device for a piezoelectric vibrating device that performs frequency adjustment by ion milling using a tuning fork type crystal vibrating element.

  The frequency adjustment device for a piezoelectric vibration device according to the present invention includes a frequency adjustment unit 1, a frequency counter circuit 21 and a frequency counter circuit 22 that receive frequency signals from the frequency adjustment unit 1, and a control unit that receives data measured by each frequency counter circuit. It consists of three.

  The frequency adjusting unit 1 adjusts the frequency of the tuning fork type crystal vibrating element 132 housed in the package 13 having the opening by ion milling while exciting the tuning fork type crystal vibrating element 132, and the frequency signal at the time of adjustment Is output to the outside.

  Although not shown, the tuning-fork type quartz vibrating element 132 has a tuning-fork type shape that connects a pair of vibrating arms and one of these vibrating arms, and is formed on an opposing main surface of one vibrating arm. And the excitation electrode formed on the opposite side surface of the other vibrating arm are connected in common, and the excitation electrode formed on the opposite side surface of the one vibrating arm and the opposite main surface of the other vibrating arm are formed. In this configuration, the excitation electrode is connected in common. Tuning fork bending vibration is performed by the electrode configuration.

  The package 13 that accommodates the tuning fork type crystal resonator element 132 has a box-shaped structure having an opening, and has a multilayer structure made of ceramic, an electrode pad that holds the tuning fork type crystal resonator element, and an external device that leads the electrode pad to the outside. Connection terminals 131a and 131b are provided.

  Each package is stored in a pallet 11. The pallet 11 is made of a metal material made of SUS304 stainless steel or the like, a ceramic material, or the like, and has a configuration in which storage portions 4a for holding packages are arranged in a matrix. Each storage portion 4a has a concave shape opened upward, and a small opening (ion beam transmission hole) 111 through which an ion beam passes is formed at the bottom. In addition, since the ion beam B is irradiated to the opening portion, a double structure in which a material resistant to ion etching is used to protect the pallet may be used.

  An ion gun 12 is disposed below the pallet 11. The ion gun 12 has a cylindrical shape as a whole, and the internal configuration is not shown, but a hot cathode (filament), an anode (anode) formed in a cylindrical shape in front of the hot cathode, and a front surface of the anode are provided. A shield grid, an acceleration grid provided in front of the shield grid, and a supply port for supplying an inert gas therein. The acceleration grid serves as a radiation port for the ion beam B, and ion particles are emitted in the form of a beam. Although not shown, in the present embodiment, the acceleration grid has a plurality of grid openings, and these grid openings are arranged in a substantially circular shape as a whole.

  A shutter 121 is disposed in front of the acceleration grid of the ion gun 12. The shutter 121 is arranged in the irradiation path of the ion beam B, and the irradiation of the ion beam to the excitation electrode (metal film) of the tuning-fork type crystal vibrating element is controlled by opening and closing the shutter 121. In this embodiment, the shutter 121 is arranged in parallel with the plane of the acceleration grid, which is the radiation surface of the ion gun, but may be arranged in a non-parallel state.

  The oscillation circuit unit 14 generates a frequency signal of the tuning-fork type crystal vibrating element whose frequency is being adjusted, and the frequency signal is output to a multiplier 2a described later. In addition, the oscillation circuit unit 14 includes contact probes 141 and 142 that come into contact with the external connection portions 131a and 131b of the package in the vacuum chamber. The contact probe is moved up and down by an actuator (not shown), and operation control is performed corresponding to the above-described frequency adjustment operation. The contact probe may move in synchronism with the movement of the ion gun with a pair of terminal configurations, or a plurality of contact probe sets may be prepared and connected to the frequency measurement unit by switching the relay to perform frequency measurement. Also good. The frequency signal generated by the oscillation circuit unit 14 becomes an output signal to the frequency adjustment unit.

  The frequency counter circuits 21 and 22 are configured to convert an input analog signal into a digital signal (pulse signal) and measure (count) the number of pulses. The frequency counter circuit 21 and 22 receives the frequency signal from the frequency adjustment unit 1, Measure the frequency of the element. Specifically, by setting the gate opening time based on the reference clock of each frequency counter circuit 21, 22 and measuring the number of pulses input within the gate opening time, the frequency of the tuning-fork type crystal vibrating element under adjustment is adjusted. taking measurement. The measurement data is transmitted to the control unit 3.

  As shown in FIG. 3, the frequency counter circuits 21 and 22 shift the predetermined time intervals for measuring the frequency from the frequency adjusting unit 1. Specifically, when the fixed time (gate open time) for measuring the frequency is set to 10 ms (milliseconds), the gate of the frequency counter circuit 22 is opened about 5 ms after the gate of the frequency counter circuit 21 is opened. Opening and closing are repeated sequentially. Each frequency counter circuit closes the gate, then transmits the measured measurement data to the control unit 3, and after completing the transmission, opens the gate again to measure the frequency. Thus, the measurement data can be transmitted from the frequency counter circuits 21 and 22 to the control unit about every 5 ms. In practice, the transmission time of measurement data requires about 1 ms.

The control unit 3 controls the adjustment operation to the frequency adjustment unit 1, controls the measurement operation of the frequency counter circuits 21 and 22, and receives the measurement data, and compares the received measurement data with the set (target) frequency. Do. Then, based on the comparison result, it is determined whether to end or continue the frequency adjustment for the tuning fork type crystal resonator element.

Specifically, when frequency adjustment is performed by reducing the adjustment metal film, which is a mass for frequency adjustment formed in advance on the tuning-fork type crystal vibrating element, such as ion milling, the frequency is reduced by reducing (removing) the adjustment metal film. Rises. The control unit 3 transmits the measurement start signals S4 and S6 to each frequency counter circuit at a timing shifted from each other, thereby opening the gate in a state where one frequency counter circuit is delayed, and measuring the frequency for a certain period of time. . After each fixed time, the measurement data S5 and S7 are transmitted to the control unit 3 from the respective frequency counter circuits.

The measurement data S5 and S7 received from the frequency counter circuits 21 and 22 are compared with the set frequency recorded in the control unit 3, and if the measurement data is higher than the set frequency, it is determined that the frequency adjustment is finished, and the frequency adjustment unit 1 is sent to the control signal for completion of adjustment. If the measurement data is lower than the set frequency, it is determined that the frequency adjustment is to be continued, and the adjustment end control signal is not transmitted to the frequency adjustment unit 1. Thereby, the frequency adjustment operation is continued. Note that the frequency adjustment operation may be continued by transmitting a control signal for continuing the adjustment according to the setting.

Next, an embodiment of a frequency adjusting device for a piezoelectric vibrator will be described. As shown in FIG. 2, in the frequency adjustment unit 1, the tuning fork type crystal resonator element 132 formed with the excitation electrode and the adjustment metal film which is the mass for frequency adjustment is stored in the pallet 11 in a state of being stored in the package. ing. The pallet 11 is configured to have the storage portions 4a in a matrix shape, and a package 13 is stored in each storage portion.

These pallets 11 are arranged in a vacuum chamber in which ion milling can be performed, and an ion beam is applied to the adjustment metal film of the tuning-fork type crystal vibrating element 132 sequentially stored in the package in the pallet by the ion gun 2 to adjust the adjustment metal film. Reduce the mass of At this time, the tuning-fork type crystal vibrating element whose frequency is being adjusted is excited by the oscillation circuit unit 14, and the frequency signal gradually changes (increases) corresponding to the decrease in the mass. The frequency of the tuning fork type crystal vibrating element is measured via contact probes 141 and 142 in which the frequency signal is contact-connected to the external connection electrodes 131a and 131b of the package. The frequency signal is output from the oscillation circuit unit 14 to a multiplier 2a described later.

The measured frequencies are transmitted to the frequency counters 21 and 22 as frequency signals S2 and S3, respectively. The frequency signals S2 and S3 are multiplied by a multiplier 2a arranged in front of each frequency counter circuit, and the multiplied frequency is obtained. The frequency signal is branched and transmitted to the frequency counters 21 and 22. For example, the frequency is multiplied by 3000 times, and the frequency 32.768 KHz of the tuning-fork type crystal vibrating element is multiplied to 98.304 MHz and transmitted to the frequency counter circuits 21 and 22, respectively. By such processing, even if the gate opening time is 10 ms, the minimum unit of frequency measurement can be 1 ppm, which contributes to highly accurate frequency adjustment.

As shown in the timing chart of FIG. 3, the frequency counter circuits 21 and 22 open the gate of the frequency counter circuit at a time of 10 ms based on the measurement start signal, and transmit the measurement data to the control unit 3 after closing the gate. The operation is repeated. As described above, as shown in FIG. 3, the frequency counter circuits 21 and 22 shift the fixed time intervals for measuring the frequency from the frequency adjustment unit 1. Specifically, the fixed time (gate opening time) for measuring the frequency is set to 10 ms (milliseconds), and the setting is stored in each frequency counter circuit. In this state, a measurement start signal is transmitted from the control unit 3 to the frequency counter circuit 21, and the frequency counter circuit 21 opens the gate for 10 ms based on the reception of the measurement start signal and the above setting. While the gate is open, a busy signal (not shown) is transmitted to the control unit.

About 5 ms after the gate opening of the frequency counter circuit 21, the control unit 3 sends a measurement start signal S 6 to the frequency counter circuit 22. The frequency counter circuit 22 opens the gate for 10 ms based on the reception of the measurement start signal and the above setting. To do. While the gate is open, a busy signal (not shown) is transmitted to the control unit.

When the gate of the frequency counter circuit 21 is closed, the transmission of the busy signal is stopped, and based on the stop of the busy signal, a read command signal (not shown) is transmitted from the control unit 3 to the frequency counter circuit 21. Based on the reception of the read command signal, the measurement data measured from the frequency counter circuit 21 is transmitted to the control unit 3.

Further, about 5 ms after the gate of the frequency counter circuit 21 is closed, when the gate of the frequency counter circuit 22 is closed, the transmission of the busy signal is stopped, and a read command is sent from the control unit 3 based on the stop of the busy signal. A signal (not shown) is transmitted to the frequency counter circuit 22. Based on the reception of the read command signal, the measurement data measured from the frequency counter circuit 22 is transmitted to the control unit 3.

Thus, the opening and closing of the gates of the frequency counter circuits 21 and 22 are successively repeated. As described above, after closing the gate from each frequency counter circuit, the measured measurement data is transmitted to the control unit 3, and after the transmission is completed, the gate is opened again to measure the frequency. Thus, the measurement data can be transmitted from the frequency counter circuits 21 and 22 to the control unit about every 5 ms. The gate opening time of the frequency counter circuit may be configured by a direct command from the control unit. The gate opening signal and the gate closing signal from the control unit are transmitted with a predetermined time interval, and the frequency counter circuit The operation may be controlled.

The operations of the frequency counter circuits 21 and 22 are controlled by a command from the control unit 3. By transmitting the measurement start signal as described above, the frequency counter circuit opens the gate. Further, a read command signal is transmitted to the frequency counter circuit based on the reception stop of the busy signal, and measurement data from the frequency counter circuit is received.

FIG. 4 is a graph showing timing of frequency measurement by the frequency counter circuits 21 and 22 in frequency adjustment by ion milling. The measurement C22 by the frequency counter circuit 22 is started in the middle (intermediate) of the measurement C21 by the frequency counter circuit 21, and the frequency measurement is performed in a state of being alternately shifted. After the frequency measurement, the measurement data is transmitted to the control unit 3, and the accuracy related to the measurement is improved.

FIG. 5 is a diagram showing a frequency distribution when the frequency of a plurality of tuning fork type crystal vibrating elements according to the present invention is adjusted. The variation is suppressed as compared with the frequency distribution when the frequency of the conventional tuning fork type crystal resonator elements shown in FIG. 6 is adjusted, and the frequency adjustment is performed in a state of being concentrated in the vicinity of the set frequency.

In this way, the control unit 3 alternately receives measurement data from the frequency counter circuits 21 and 22, compares it with a preset set frequency, and transmits a control signal to the frequency adjustment unit 1 when the set frequency is exceeded. Then, the frequency adjustment operation for the tuning fork type crystal resonator element is terminated. Then, the frequency adjustment for the next tuning-fork type crystal vibrating element is performed in the same procedure. When the frequency adjustment of the tuning fork type crystal vibrating elements stored in all the packages of the pallet is completed, the process proceeds to a subsequent process such as a thermal stabilization process.

In the above description of the embodiment and examples, an example of frequency adjustment in which the mass for frequency adjustment is reduced by ion milling has been described. For example, sand blasting that irradiates an adjustment region with an electron beam, a laser beam, or a fine particle body. A method of reducing the frequency adjustment mass by a method or the like may be applied.

The present invention can also be applied to an apparatus that adds mass for frequency adjustment. Specifically, a partial vapor deposition method in which a metal film is partially formed in the frequency adjustment region can be used. When adding the mass for frequency adjustment in this way, the adjustment is advanced by lowering the frequency of the piezoelectric vibration element. Therefore, it is necessary to end the frequency adjustment when the frequency becomes lower than the set frequency.

In addition, although two frequency counter circuits are used, a configuration in which three or more frequency counter circuits are used and measurement is sequentially advanced may be employed. The gate open time in the frequency counter circuit, that is, the frequency measurement time is set to 10 ms, but may be set to be longer (for example, 12 ms) or shorter (for example, 8 ms). If it is set to 10 ms or less, the accuracy of frequency measurement may be reduced, but the time required for measurement can be shortened, which contributes to the improvement of productivity. In addition, when the time is set to 10 ms or more, the accuracy of frequency measurement is improved, but the time required for measurement becomes longer.

Further, although the frequency of the tuning fork type crystal resonator element is multiplied by 3000 times by the multiplier, it may be multiplied by 3000 times or more (for example, multiplied by 5000 to 10000 times, etc.). In this case, the resolution in frequency adjustment is increased and the adjustment accuracy is improved.

  Further, although a tuning fork type quartz crystal vibrating element housed in a surface mount type package is illustrated as a piezoelectric vibrating element, it may be applied to a cylinder type quartz crystal resonator connected to a base with lead terminals. Further, an AT-cut quartz crystal vibration element or a piezoelectric vibration element made of a piezoelectric material other than quartz may be used.

  In the case of an AT-cut quartz resonator, the frequency is adjusted by forming a mass-added metal film on the excitation electrode, or the frequency is adjusted by partially reducing the thickness of the excitation electrode. In the case of mass addition, an example in which a metal film is additionally formed by partial vapor deposition can be given. Moreover, when reducing the film thickness of an excitation electrode, the example which removes a part of metal film by ion milling can be given. In addition to the crystal resonator, the present invention may be applied to a crystal oscillator that houses a crystal resonator element and an oscillation circuit IC.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit, gist, or main features. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  Applicable for mass production of crystal units.

DESCRIPTION OF SYMBOLS 1 Frequency adjustment part 21 and 22 Frequency counter circuit 3 Control part

Claims (2)

A frequency adjustment device for a piezoelectric vibration device that performs frequency adjustment by adding a mass for frequency adjustment to the piezoelectric vibration element,
A frequency adjustment unit for adding mass for frequency adjustment to the piezoelectric vibration element;
A plurality of frequency counter circuits that receive the frequency signal output from the frequency adjustment unit and measure the frequency for a predetermined time;
Receives measurement data of the frequency measured by each frequency counter circuit, determines whether or not the received signal is equal to or lower than a set frequency, and transmits a frequency adjustment stop signal to the frequency adjustment device when the frequency is equal to or lower than a predetermined frequency. A control unit,
The plurality of frequency counter circuits mutually shift a predetermined time interval for measuring the frequency from the frequency adjusting unit, and after each frequency measurement for the predetermined time, transmits the measurement data to the control unit. Frequency adjustment device for vibration devices. A frequency adjustment device for a piezoelectric vibration device that performs frequency adjustment by reducing a mass for frequency adjustment in a piezoelectric vibration element,
A frequency adjustment unit for reducing the frequency adjustment mass in the piezoelectric vibration element;
A plurality of frequency counter circuits that receive the frequency signal output from the frequency adjustment unit and measure the frequency for a predetermined time;
While receiving the measurement data of the frequency measured by each frequency counter circuit, it is determined whether or not the received measurement data is equal to or higher than a predetermined frequency, and if it is equal to or higher than the predetermined frequency, a frequency adjustment stop signal is sent to the frequency adjustment device. A control unit for transmitting,
The plurality of frequency counter circuits mutually shift a predetermined time interval for measuring the frequency from the frequency adjusting unit, and after each frequency measurement for the predetermined time, transmits the measurement data to the control unit. Frequency adjustment device for vibration devices.

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