JPH10163782A - Frequency control method for crystal oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency control method for crystal oscillator with which frequency control is enabled at low cost without deviating the frequency of crystal oscillator. SOLUTION: A crystal oscillator 1 is set at the lower part of case 10. Ions are injected from an ion gun 16 toward an insulator 14 provided inside the case 10 and insulating particles are scattered from the insulator 14 by its collision energy and stuck on the surface of crystal oscillator 1. During this operation, the frequency of crystal oscillator 1 is measured by a frequency measuring part 30 and when it reaches a target frequency, the emission of ions from an ion gun 16 is stopped. The insulator 14 is inexpensive and the insulating particles stuck on the crystal oscillator 1 do not affect the capacitance of crystal oscillator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the frequency of a crystal unit by attaching non-conductive particles to the surface of the crystal unit.

[0002]

2. Description of the Related Art A quartz oscillator is formed by forming electrodes on a main surface of a quartz plate. The electrode is generally formed by depositing a conductive material such as gold or silver in the form of a thin film. The frequency of the crystal unit depends on the thickness of the quartz plate, but the thickness of the quartz plate tends to vary, so that the frequency also tends to vary. Therefore, after the electrodes are formed on the quartz plate, the frequency is adjusted by changing the thickness of the electrodes. Hereinafter, a conventional method of adjusting the frequency of the crystal resonator will be described.

FIG. 4 is a cross-sectional view of a conventional crystal oscillator frequency adjusting device, and FIG. 5 is a perspective view of the crystal oscillator after the frequency adjustment. In FIG. 4, a crystal resonator 1 is formed by forming electrodes 3 on both surfaces of a crystal plate 2. The electrode 3 is formed by evaporating silver, and is formed thin (on the side where the frequency is higher than the target frequency). Reference numeral 4 denotes a masking component, and a pattern hole 5 is opened.

Next, the operation will be described. As shown in FIG.
The pattern hole 5 is aligned with the electrode 3 on the quartz plate 2 and silver is vapor-deposited (see the arrow) to form the additional electrode 3 a on the electrode 3. During that time, the frequency of the quartz oscillator 1 is measured by a frequency measuring means (not shown), and when the frequency of the quartz oscillator 1 reaches the target frequency, the deposition of silver is stopped.

[0005]

As described above, in the conventional method, the same conductive material as the electrodes such as gold and silver is added to the electrodes 3 so that the mass of the electrodes 3 is adjusted to the mass corresponding to the target frequency. It is. However, in recent years, since the size of the crystal resonator has been increasingly reduced, it has become difficult to align the pattern hole 5 of the masking component 4 with the electrode 3. If the pattern hole 5 is not accurately aligned with the electrode as shown in FIG. 4, the additional electrode 3a is not only located on the surface of the electrode 3 but also on the surrounding quartz plate 2 as shown in FIGS.
It is added in the form protruding up to the surface of. The protrusion of the additional electrode 3a made of a conductive material substantially increases the area of the electrode 3, and as a result, the capacitance of the electrode 3 changes and the capacitance of the crystal unit 1 shifts, or abnormal oscillation occurs. There was a problem.

In this method, gold and silver, which are the materials of the electrodes 3a, are expensive, so that the material cost is high, and this causes high cost together with a large amount of power energy consumed when depositing these conductive materials. As shown in FIG. 4, in the electrode material adding step, the conductive material to be deposited also adheres to the periphery of the opening of the masking component 4, and becomes a deposited layer 3b with the repetition of the same step. It becomes useless when it becomes. For this reason, the masking part 4 needs to be periodically replaced with a new one.
Since the masking part 4 requires precision processing, the production cost is high, and replacement of the masking part 4 is also a factor of high cost. As described above, the conventional method has a problem that the cost is high as a whole.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of adjusting the frequency of a crystal resonator which can perform frequency adjustment at low cost without deteriorating the oscillation characteristics of the crystal resonator.

[0008]

According to the method of adjusting the frequency of a crystal unit according to the present invention, a crystal unit having electrodes formed on the surface of a crystal plate is placed inside a casing, and then the inside of the casing is placed inside the casing. Non-conductive particles are scattered toward the crystal unit and adhere to the surface of the crystal unit, and the thickness of the layer of the attached non-conductive particles is changed to adjust the frequency of the crystal unit.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, since a non-conductive material is used as a material for an additional electrode, the capacitance does not change regardless of the range in which the additional electrode is formed. Can be obtained.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a crystal oscillator frequency adjusting device according to an embodiment of the present invention. FIG. 2 is an enlarged view of a crystal oscillator and a receiving portion of the crystal oscillator frequency adjusting device.
3A and 3B are a perspective view and a side cross-sectional view of the crystal resonator after frequency adjustment of the crystal resonator.

First, the overall structure of the crystal oscillator frequency adjusting device will be described with reference to FIG. In FIG. 1, a casing 10 is provided to maintain an atmosphere in which insulating particles are attached at a predetermined degree of vacuum, and a vacuum pump 13 is connected to the casing 10 via a pipe 12. The casing 10 is provided with a vacuum break valve 19 for introducing the atmosphere when the vacuum is released.

In the casing 10, an insulator 14 attached to the crystal unit by sputtering and a mounting plate 15 for holding the insulator 14 are disposed in an inclined posture. As the insulator 14, a non-conductive substance such as quartz or quartz, which is mainly composed of SiO ₂ , or silicon is used. An ion gun 1 is provided on the side of the casing 10.
6 is attached, and an insulator 14 mounted inside the casing 10 is used as a target to emit argon ions and electrons.

An opening 17 is formed on the bottom of the casing 10. A table 20 is provided below the opening 17.
Are arranged. On this table 20, a case 21 in which the crystal unit 1 to be frequency-adjusted is stored is placed. As shown in FIG. 2, a clamper 23 is provided on the table 20 for clamping the case 21 from the left and right.
Is provided. The table 20 is mounted on the arm 25 of the movable table 24 by a support 26. The movable table 24 positions the case 21 in the opening 17 by moving the table 20 in the horizontal direction and the vertical direction (see the case 21 shown by a chain line in FIG. 1). In that state, the table 20 is
Is pressed against the bottom surface 18 of the casing 20 to seal between the sealing material 27 mounted on the surface of the table 20 and the casing bottom surface 18.

The lead 7 of the electrode of the crystal unit 1 held in the bottom of the case 21 (FIG. 3A)
A terminal 28 that is electrically connected to the terminal 28 is provided. As shown in FIG. 2, two probes 29 are provided on the upper surface of the table 20 so as to contact the terminals 28. When the case 21 is clamped at a predetermined position and contacts the terminals 28, the crystal vibration inside the case 21 is increased. Conduction with child 1. This table 20
The probe 29 is guided to the electrode 34 on the lower surface of the arm 25 by the wiring 35 via the support 26 and the arm 25 of the movable table 24, and the frequency measuring unit 30 is connected via the lead wire 33.
It is connected to the. In FIG. 2, reference numeral 36 denotes a quartz oscillator 1
And a wire 37 for connecting the lead portion 7 and the internal wiring 38 to each other. The internal wiring 38 is connected to the terminal 28.

The frequency measuring unit 30 applies a voltage to the quartz oscillator 1 in parallel with the step of attaching insulating particles to the quartz plate 2 and measures the oscillation frequency of the quartz oscillator 1. Control unit 3
1 receives the measurement result from the frequency measurement unit 30, processes the data, and controls the frequency measurement unit 30 and the voltage control unit 32. The voltage controller 32 controls the operation of the ion gun 16 based on the data processing result of the controller 31.

This frequency adjusting device for a crystal oscillator has the above-described configuration, and its operation will be described below. First, in FIG. 1, a case 21 for holding a target crystal resonator 1 is set on a table 20. Next, Table 2
0 is conveyed by the movable table 24, and the case 21 is positioned in the opening 17 on the bottom surface of the casing 10. In this state, vacuum suction by the vacuum pump 13 is started, and a predetermined degree of vacuum is maintained.

In this state, the crystal unit 1 is connected to the frequency
0, and the oscillation frequency of the placed crystal unit 1 is continuously measured, and the measurement result is transmitted to the control unit 31. If the result is lower than the target frequency,
The ion gun 16 from the control unit 31 through the voltage control unit 32
A signal is output to the ion gun 16 and the insulator 1 serving as a target holding argon ions and electrons on the mounting plate 15
Inject to 4

The insulating particles struck out of the surface of the insulator 14 by the collision energy of these ions are scattered in a vacuum and adhere to the surface of the crystal unit 1 in the form of a thin film. In this embodiment, no masking component is used, and as a result, the added thin film 3c of the insulating material covers not only the electrode portion 3 but also the entire surface of the quartz plate 2 as shown in FIGS. 3 (a) and 3 (b). Will do. In this way, the thin film 3c of the insulator attached to the crystal unit 1 has the same effect as increasing the mass of the electrode unit 3, and lowers the oscillation frequency of the crystal unit 1.

During the process of adding insulating particles, the quartz oscillator 1
The oscillation frequency is continuously measured by the frequency measurement unit 30. By feeding back the deviation between the measurement result and the target frequency, the adhesion of the insulating particles to the crystal unit 1 at the time when the frequency coincides with the target frequency is performed. To stop. This completes the frequency adjustment.

Thereafter, the atmosphere is introduced into the casing 10 by opening the vacuum breaking valve 19, and the pressure in the casing 10 becomes equal to the atmospheric pressure. Here table 2
0 is lowered, and the case 21 is sent to the next step.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the insulating particles are adhered to the entire surface of the crystal unit without using the masking component. The insulating particles may be attached only on the electrodes. In this case, even if the insulating particles protrude from the electrodes and adhere to the surface of the quartz plate, they do not affect the capacitance.

In the above embodiment, the ion gun 16
While the insulating particles are continuously attached to the crystal unit 1 by continuously injecting ions from the
When the frequency reaches a predetermined value, the injection of ions from the ion gun 16 is stopped. However, the insulating particles are intermittently adhered to the crystal unit 1 little by little. The frequency may be measured by the frequency measuring unit 30 at the time of stopping, and a predetermined amount of insulating particles may be adhered to the crystal unit 1 while repeating the adhesion and the measurement.

Alternatively, after a large number of non-conductive particles (insulating particles) are attached to the crystal unit 1, the frequency is measured, and then the extra non-conductive particles attached by dry etching or the like are scraped off. A predetermined frequency may be obtained. The means for adhering the non-conductive material to the crystal unit is not limited to the ion gun 16, but may be a plasma sputtering unit or a vapor deposition unit. In short, a small amount of non-conductive particles may be applied to the surface of the crystal unit. Any thin film forming means that can be attached one by one may be used.

Furthermore, in the above embodiment, the insulator 14 such as quartz or quartz is used as the material of the non-conductive particles, but silicon may be used. In this case, silicon can be easily removed by etching, so that a desired quartz oscillator can be obtained in a short time, and the adhesion to the quartz plate 2 is very good, and a highly reliable quartz oscillator can be obtained.

[0025]

As described above, according to the present invention, since the non-conductive material is used as the material of the additional electrode, there is no change in the capacitance regardless of the range of the additional electrode, and the frequency can be adjusted accurately by performing accurate frequency adjustment. A quality crystal oscillator can be obtained.

In addition, expensive gold or silver is used as a material for the additional electrode, a large amount of power is consumed in the step of depositing these by vapor deposition, and precision masking parts requiring high manufacturing costs are used. , Are eliminated, and low-cost frequency adjustment is realized. Also,
By using a non-conductive material such as a quartz plate or quartz made of the same material as the quartz plate, better adhesion to the quartz plate can be obtained. Of the crystal plate can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a crystal oscillator frequency adjusting device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a crystal unit and a receiving unit of the crystal unit frequency adjusting apparatus according to one embodiment of the present invention;

FIG. 3 (a) is a perspective view of the crystal unit after frequency adjustment of the crystal unit according to one embodiment of the present invention; and (b) is a crystal oscillator after frequency adjustment of the crystal unit according to one embodiment of the present invention. Side sectional view of child

FIG. 4 is a cross-sectional view of a conventional crystal oscillator frequency adjuster.

FIG. 5 is a perspective view of a conventional crystal unit after frequency adjustment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz crystal oscillator 2 Quartz plate 3 Electrode 4 Masking part 5 Pattern hole 10 Casing 14 Insulator 15 Mounting plate 16 Ion gun 30 Frequency measurement part

Claims (1)

[Claims] 1. A quartz oscillator having electrodes formed on a surface of a quartz plate is disposed inside a casing, and non-conductive particles are scattered toward the quartz oscillator inside the casing to form the quartz crystal. A method of adjusting the frequency of a crystal resonator, wherein the frequency of the crystal resonator is adjusted by changing the thickness of a layer of non-conductive particles attached to the surface of the resonator.