JPH03289209A - Piezoelectric vibrator and its frequency regulating method - Google Patents

Abstract

PURPOSE:To attain frequency regulation continuously and efficiently in air by providing a frequency regulating body in spiral from the inward to the outward sputtered from the frequency regulating object on an electrode corresponding to the frequency regulating object. CONSTITUTION:A YAG laser beam 12 transmits through a glass cover 1 and sputters only a metallic coat film 9 selectively and momentarily. The sputtered metal is adhered to a frequency adjustment body 10 continuously in spiral from inward to outward on the electrode 17 arranged to a crystal vibrator 6 and the oscillating frequency of the crystal vibrator 6 is decreased by the mass addition effect. Moreover, the YAG laser beam 12 is swept and the processing above is repeated till a prescribed setting frequency is reached. Thus, the frequency regulation in air is attained, and the frequency regulation is implemented continuously in a short time with simple installation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a piezoelectric vibrator used as a reference signal generation source for various electronic devices, and a method for adjusting its frequency.

BACKGROUND OF THE INVENTION Piezoelectric vibrators using crystals or the like have various vibration modes depending on the purpose of use, but the thickness shear mode is generally used at present.

In this thickness shear mode, the resonant frequency of the piezoelectric vibrator changes in inverse proportion to the thickness of the diaphragm. Furthermore, it is known that the resonant frequency decreases due to the effect of adding mass to the electrodes, and this mass adding effect is used to adjust the resonant frequency.

A conventional piezoelectric vibrator and its frequency adjustment method will be described below.

FIG. 8 shows an internal structure diagram of a crystal resonator commonly used in conventional piezoelectric resonators, and FIG. 9 is a schematic diagram showing a method for adjusting the frequency of the crystal resonator.

In FIG. 8, electrodes 16 are made by depositing metal such as silver or aluminum to a thickness of several thousand layers on both sides of a crystal plate 13, which has been precisely polished (sometimes polished) to adjust the frequency.
and attach it to the base 14 of the retainer with the supporter 18.
It is attached to. Although this supporter 18 is plate-shaped in the figure, it may also be linear depending on various conditions. In addition, this supporter 18 serves to support the crystal plate 13 and also serves as an electrical conductor, and whether it is in the form of a plate or a wire, the contact point with the crystal plate 13 is set to prevent the crystal plate 13 from falling off. It is fixed with Rt adhesive 19. The input/output terminals 15 pass through the base 14, and a metal cover 20 is further bonded to the outer periphery of the base 14 to seal it. Furthermore, crystal plate 1
On the electrodes 16 of No. 3, a frequency adjustment body 17 for making final adjustment of the frequency is uniformly added in a shape slightly smaller than the electrodes 16 of the crystal plate 13.

FIG. 9 shows a method of adjusting the frequency of the crystal resonator before hermetically sealing it. That is, in the vacuum chamber 22, the one shown in FIG. 8 before being covered with the metal cover 20 is placed. After creating a high vacuum atmosphere in the vacuum chamber 22, the evaporation source 24 is electrically heated, and the metal 2, such as silver or aluminum, for frequency adjustment is melted by heating.
3 is evaporated, and the electrode 1 of the crystal plate 13 is exposed through the mask 21.
It is uniformly deposited on the electrode 6 in a shape slightly smaller than that of the electrode 16. At the same time, the counter 28 reads the oscillation frequency of the crystal oscillator during silver deposition, and when the oscillation frequency drops to a certain set value, the comparator 27 closes the shutter 25 and stops the deposition, thereby adjusting the oscillation frequency. Was.

Problems to be Solved by the Invention However, the conventional frequency adjustment method using the general vacuum evaporation method requires a high vacuum of 10-'torr or more, and requires expensive vacuum equipment including the vacuum chamber 22, etc. In addition to incurring costs, adjusting the frequency required extra time for vacuuming and other tasks, impairing productivity. In addition, frequency adjustment must be performed before hermetic sealing, and as the resonant frequency of the crystal oscillator changes due to hermetic sealing such as resistance welding or cold welding, the resonant frequency of the finished product can be adjusted with high precision. It was extremely difficult to adjust. Furthermore, as the frequency band becomes higher, the crystal resonator becomes smaller and the electrode 16 of the crystal plate 13 also becomes smaller. Not only is it extremely difficult to adjust the frequency as some parts of it stick out, but also
This also affected reliability by increasing the equivalent resistance.

Therefore, it is an object of the present invention to provide a device that allows resonance frequency adjustment to be performed with high precision and high productivity.

Means for Solving the Problems and a distant relative of the above object, the present invention provides an airtight container, at least a portion of which is translucent, a diaphragm provided in the airtight container, and a surface of the diaphragm. an electrically conductive means introduced into the airtight container from the outside and connected to the electrodes on the front and back surfaces, and the airtight container corresponding to the light-transmitting portion of the airtight container. and a frequency adjuster provided in the inner part, and on the electrode part corresponding to the frequency adjuster, there is a continuous or discontinuous wave scattered from the frequency adjuster from the inside to the outside. It is equipped with a spiral frequency adjuster. The manufacturing method includes irradiating a laser beam from the outside of the airtight container through the light-transmitting part to the frequency adjustment object provided on the inner surface of the airtight container, scattering the frequency adjustment object by this irradiation, and scattering the frequency adjustment object. The frequency of the diaphragm is adjusted by attaching the frequency adjusting material onto the electrodes of the diaphragm in a continuous or discontinuous spiral shape from the inside to the outside.

Effects of the present invention With the above configuration, it is possible to adjust the frequency in the atmosphere by using a finished product in which the vibrating piece is hermetically sealed in an airtight container, and vacuum equipment such as a vacuum container is not required, resulting in a simple equipment configuration of N. Since the frequency can be adjusted continuously in a short period of time, production efficiency can be significantly improved. Further, since the frequency is adjusted after hermetically sealing each piece, there is no need to consider frequency variations in subsequent processes, and frequency deviations in the finished product can be reduced.

Embodiment FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention.
A rectangular crystal oscillator 6 with electrodes 7 arranged on its front and back surfaces is supported and electrically connected to the holding portion 4 of the lead terminal 3, which is used as an example of an electrically conductive means, by means of a conductive adhesive 5. . A metal coat M9 as an example of a frequency adjusting material is applied to the inner surface of the transparent glass cover 1 by vacuum deposition. The inner surface of the glass cover 1 is roughened by sandblasting, polishing, etc., and the metal coating film 9 is provided on this roughened portion. moreover,
In this embodiment, the material of the metal coating film 9 is silver, which is the same as that of the electrodes 7 formed on the crystal resonator 6. The crystal resonator 6 is hermetically sealed between the case 2 and the glass cover 1 using a sealing agent 8. In other words, the glass cover 1 and the case 2 form an airtight container.

FIG. 2 shows an embodiment of the frequency adjustment method of the present invention, and is a conceptual diagram of frequency adjustment using a laser beam after vacuum sealing. For frequency adjustment, connect glass cover 1 to case 2.
Although not shown, the lead terminal 3 is connected to an oscillator, and the oscillation frequency can be checked with a counter. Here, YAG laser light 12, which is a continuous wave light pulsed by a Q switch, is focused by a focusing lens 11 near the metal coating film 9 through a glass cover 1 from the outside. Then, the laser beam 12 is irradiated while moving from the inside to the outside of the metal coating film 9 by a galvanometer method in which the laser beam 12 is scanned using two galvanometers. Here, the galvanometer type was used to move the laser beam 12, but the two Mirane prisms are fixed to an XY table using an XY table method, or the optical fiber output optical part can be moved freely by a robot using a fiber method. It is. The YAG laser beam 12 can pass through the glass cover 1, select only the metal coating film 9, and instantly scatter it. As shown in Fig. 3, the scattered metal is deposited as a frequency adjusting body 10 on the electrode 7 arranged on the crystal resonator 6 in a continuous spiral shape from the inside to the outside, and the crystal vibration is controlled by the mass addition effect. The oscillation frequency of child 6 decreases. Furthermore, the YAG laser beam 12 is swept and repeated until a predetermined set frequency is reached. In this embodiment, a YAG laser beam was used as the laser beam 12, but the glass cover 1
Anything that can pass through can be used.

Further, although silver was used for the electrode 7 and the metal coating film 9 and was applied by a vacuum evaporation method, it is sufficient that it is stable on the electrode 7, and it is also possible to apply it by a method such as printing.

In this example, the inner surface of the glass cover 1 was roughened for the following reasons.

In other words, since the part of the metal IK9 irradiated with the laser beam 12 immediately scatters, the remaining energy of the laser beam 12 irradiated thereon will attack the electrode 7 in the future.

Therefore, the above-mentioned surface roughening was performed in order to prevent the harmful effects of the remaining energy.If the surface is roughened, the remaining energy is dispersed in the roughened and surfaced portion and then directed toward the electrode 7. This prevents the electrode 7 from being locally attacked.

According to the above frequency adjustment method, the piezoelectric vibrator itself consisting of the airtight container and the crystal resonator 6 can be placed in the atmosphere, so high vacuum equipment such as the conventional vacuum container is not required, and the structure is simple. Frequency adjustment becomes possible with equipment. Furthermore, the frequency adjustment speed can be increased compared to the conventional method, and frequency adjustment can be performed continuously and efficiently. Next, in the conventional process, after frequency adjustment, the crystal oscillator 6
is housed in a case and hermetically sealed by resistance welding or cold welding, but there was a problem that the frequency changed after hermetically sealing, but the frequency adjustment of the crystal oscillator 6 according to this embodiment Since this is done after hermetic sealing, the frequency deviation of the finished product can be reduced.

Furthermore, since the electrode 7 is not directly scraped off unlike the conventional example using the laser beam 12, the equivalent resistance of the crystal resonator 6 hardly deteriorates. In FIG. 2, even if the focal point of the laser beam 12 after passing through the focusing lens 11; 1c is set before it enters the glass cover 1, the metal coating film 9 can be scattered by the laser beam. Also, in this case, the energy of the laser beam 12 is too strong and the glass cover 1
will no longer be damaged.

4 to 7 show the frequency adjustment body 1 provided on the electrode 9.
4 and 5 show other embodiments of 0, in which continuous or discontinuous circles of different sizes are arranged approximately concentrically from the inside to the outside. It is something. Moreover, the one shown in FIG. 6 and FIG. 7 is provided with a frequency adjusting body 10 in the form of #1 winding, which is continuous or discontinuous from the inside to the outside.

Effects of the Invention As is clear from the above description, the piezoelectric vibrator and its frequency adjustment method of the present invention have the advantage that the frequency of the piezoelectric vibrator can be continuously and efficiently adjusted in the atmosphere. Furthermore, since the frequency can be adjusted after the vibrating element is hermetically sealed in the airtight container, it is possible to reduce the frequency deviation of the finished product.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway maple diagram showing an embodiment of the piezoelectric vibrator of the present invention, Fig. 2 is a sectional view showing an embodiment of the frequency adjustment method for the piezoelectric vibrator of the present invention, and Fig. 3 is a is the conventional pressure!
FIG. 9 is a half-sectional front view showing the structure of a vibrator, and a configuration diagram showing a frequency adjustment method using a conventional vacuum evaporation method. 1...Glass cover, 2...Case,
3... Lead terminal, 4... Holding part, 5
... Conductive adhesive, 6 ... Crystal resonator, 7 ... Electrode, 8 ... Sealing agent, 9 ...
... Metal coat film, 10 ... Frequency adjustment body, 11 ... Focus lens, I2 ... Laser light.

Claims (12)

[Claims] (1) An airtight container, at least a portion of which is translucent, a diaphragm provided within the airtight container, electrodes provided on the front and back surfaces of the diaphragm, and an airtight container from the outside of the airtight container. an electrically conductive means introduced into the interior thereof and connected to the electrodes on the front and back surfaces; and a frequency adjustment member provided in a portion inside the airtight container corresponding to a light-transmitting portion of the airtight container; A piezoelectric vibrator, wherein a spiral frequency adjusting body that is scattered from the frequency adjusting object and is continuous or discontinuous from the inside to the outside is provided on the electrode portion corresponding to the object. (2) In claim (1), the frequency adjustment object is a piezoelectric vibrator formed of a metal coated film provided on the inner surface of the light-transmitting part of the airtight container. (3) A piezoelectric vibrator according to claim (2), in which the electrode and the frequency adjuster are made of the same metal material. (4) An airtight container, at least a portion of which is translucent, a diaphragm provided within the airtight container, electrodes provided on the front and back surfaces of the diaphragm, and from the outside of the airtight container, The airtight container includes an electrically conductive means introduced into the airtight container and connected to the electrodes on the front and back surfaces, and a frequency adjuster provided in the inner part of the airtight container corresponding to the light-transmitting part of the airtight container. In the light-transmitting part, a laser beam is irradiated from the outside of the airtight container through the light-transmitting part to the frequency adjustment object provided in the airtight container, and the frequency adjustment object is scattered by this irradiation, and the frequency adjustment object is scattered by this irradiation. By depositing the scattered frequency adjustment material on the electrode of the diaphragm in a continuous or discontinuous spiral shape from the inside to the outside,
A piezoelectric vibrator frequency adjustment method that adjusts the frequency of this diaphragm. (5) A method for adjusting the frequency of a piezoelectric vibrator according to claim (4), wherein the frequency adjusting object is a metal coated film provided on the inner surface of a light-transmitting part of an airtight container. (6) A method for adjusting the frequency of a piezoelectric vibrator according to claim (5), wherein the metal coating film is provided on a roughened inner surface of an airtight container. (7) An airtight container, at least a portion of which is translucent, a diaphragm provided within the airtight container, electrodes provided on the front and back surfaces of the diaphragm, and an airtight container from the outside of the airtight container. an electrically conductive means introduced into the interior thereof and connected to the electrodes on the front and back surfaces; and a frequency adjustment member provided in a portion inside the airtight container corresponding to a light-transmitting portion of the airtight container; A frequency adjustment body formed by scattering from the frequency adjustment object is provided on the electrode portion corresponding to the object, and this frequency adjustment body has approximately continuous or discontinuous circles of different sizes. Piezoelectric vibrators arranged concentrically. (8) In claim (7), the frequency adjuster is a piezoelectric vibrator formed of a metal coated film provided on the inner surface of the light-transmitting part of the airtight container. (9) A piezoelectric vibrator according to claim (8), in which the electrode and the frequency adjuster are made of the same metal material. (10) An airtight container, at least a portion of which is translucent, a diaphragm provided within the airtight container, electrodes provided on the front and back surfaces of the diaphragm, and from the outside of the airtight container, The airtight container includes an electrically conductive means introduced into the airtight container and connected to the electrodes on the front and back surfaces, and a frequency adjuster provided in the inner part of the airtight container corresponding to the light-transmitting part of the airtight container. In the light-transmitting part, a laser beam is irradiated from the outside of the airtight container through the light-transmitting part to the frequency adjustment object provided in the airtight container, and the frequency adjustment object is scattered by this irradiation, and the frequency adjustment object is scattered by this irradiation. The scattered frequency adjustment objects are continuously placed on the electrodes of the diaphragm in different sizes.
Alternatively, a method for adjusting the frequency of a piezoelectric vibrator in which the frequency of the diaphragm is adjusted by attaching discontinuous circles substantially concentrically. (11) A method for adjusting the frequency of a piezoelectric vibrator according to claim (10), wherein the frequency adjusting object is a metal coated film provided on the inner surface of a light-transmitting part of an airtight container. (12) A method for adjusting the frequency of a piezoelectric vibrator according to claim (11), wherein the metal coating film is provided on the roughened inner surface of the airtight container.