JPS62109415A - Control method for frequency of piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To attain the accurate formation of an additional film on an exciting electrode by forming a pair of opposite slits to a pair of holding members and controlling the oscillation frequency after forming an additional film on the exciting electrode through a through hole of a mask. CONSTITUTION:A pair of opposite slits 3 are formed to the holding members 1a and 1b. Then a pair of opposite slits 3a and 3c are used to hold a crystal bar 7 and the other pair of slits 3b and 3d are used to hold a mask plate 9 respectively. Therefore the bar 7 is put close to the surface of the plate 9 to prevent the position shift between an exciting electrode 5 and a through hole 8. Thus the variance due to the position shift between the electrode 5 and the hole 8 can be reduced. This prevents the reduction of the crystal impedance when the frequency of a crystal oscillator is controlled and the change of the equivalent parallel capacity, etc. Thus the satisfactory electrical characteristics can be secured continuously and at the same time an additional film is formed accurately on the electrode 5 with reduced variance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a method for adjusting the frequency of a piezoelectric vibrator used as an oscillator or a resonator, and its field of application is a piezoelectric vibrator.

(Background of the Invention) In general, piezoelectric resonators made of single crystals, such as crystal resonators, have a high quality factor, or Q value, which determines the quality of their electrical characteristics, so they have traditionally been used as resonators or filter elements in communication equipment. Currently, it is incorporated into various digital devices such as electronic watches as a time reference source, and is used as the heart of the device.

(Prior Art) FIG. 3 is an example of a cross-sectional view of the configuration of this type of general crystal resonator. That is, in this crystal oscillator, one end of a pair of plate-shaped holding members 14 in which opposing slits 13 are formed is connected to the tips of a pair of lead wires 12 implanted in a base 11, and the slits 13 The outer periphery of both ends of a crystal blank 17 on which an excitation electrode 15 and an extraction electrode 16 are formed are held between the two. Usually, as shown in 5 in FIG. 4, a mask having a hole 18 approximately equal to the size of the excitation electrode is placed at a position corresponding to the excitation electrode 15, and the excitation is performed in a vapor deposition apparatus (not shown). @Metal particles were attached onto the electrode to form an additional film, thereby adjusting the frequency yA.

Then, it was configured to be sealed with a cover (not shown).

(Disadvantages of the Prior Art) By the way, when adjusting the frequency of a crystal resonator, it is said that forming a uniform additional film on the excitation electrode maintains good electrical performance of the crystal resonator. For example, the fifth
As shown in the plan view of the crystal piece in the figure, if the excitation electrode 15 and the additional film 20 indicated by the dotted line frame are significantly misaligned, the mass of each part in the excitation chamber may be different. Q and crystal impedance value may be lowered, and crystal blank 1
The additional film 20 attached to the plate surface of 7 changes the equivalent parallel capacitance and impairs the electrical characteristics of the crystal resonator. Therefore, in forming the additional film, alignment between the excitation electrode and the hole in the mask is extremely important. However, since the opening end of the mask 19 is brought into contact with the flange part and the alignment between the hole and the excitation electrode is shifted, in reality, the alignment between the two is difficult due to the dimensional accuracy of the numerous bases and masks. This is not the case, and the current situation is that there are large variations between each crystal oscillator.

(Objective of the present invention) An object of the present invention is to provide a frequency adjustment method that can accurately form an additional film on an excitation electrode with little variation.

(Characteristics of the Invention) The present invention has a pair of holding members each having a pair of opposing slits, and one pair of opposing slits (1) and 2 (2) having excitation electrodes attached to the outer periphery of both ends of the piezoelectric piece. A mask is held, which is electrically and mechanically connected, and has a through hole bored at a position corresponding to the excitation electrode in the other pair of opposing suction electrodes. Special effects are created by forming an additional film to adjust the vibration frequency.

(Embodiments of the Invention) An embodiment of the method for adjusting the frequency of a crystal resonator according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a holding member 1 applied to this embodiment attached to a base 2. As shown in FIG. That is,
This set of holding members 1a, 1b has two slits 3a, 3b and 3c, 3, respectively, in a direction perpendicular to the surface of the base 2.
d are arranged in parallel, one end of which is connected to the tip of a lead wire 4 that insulates and protrudes from the surface of the base 2, for example, by spot welding or the like. Then, as shown in Figure 2, (ζ
, one opposing sleeve 1. of this holding member 1a, 1b.
3a and 3c have rectangular excitation electrodes 5 on both main surfaces, and extraction electrodes 6 extending from the excitation electrodes 5 to the outer periphery at both ends.
Insert the lower ends of both ends of the rectangular crystal piece 7 with the
The holding members 1a and 1b are bent to connect electrically and mechanically. Next, the other pair of slits 3b and 3d have a hole 8 whose position corresponds to the size of the excitation electrode 5, and the lower ends of both ends of a mask plate 9 having approximately the same size as the crystal piece 7. Insert the crystal piece 7 and hold it with the plate surface facing each other.

Then, the crystal oscillator to which this mask plate 9 is attached is placed in a vapor deposition apparatus (not shown), and the metal particles coming from the vapor deposition source are passed through the holes 8 of the mask plate 9 and deposited on the excitation electrode, and a predetermined frequency is set. An additional film (not shown) is formed so that Therefore, according to the crystal resonator deposition method according to this embodiment, a pair of opposing slits 3 are provided in the holding members 1a and 1b.
, one opposing slit 1-3a, 3c is a crystal piece, and the other opposing slit 3b, 3c (is a mask plate 9).
Since the plate surfaces of the crystal piece 7 and the mask plate 9 are brought close to each other, it is possible to prevent the excitation electrode 5 and the through hole 8 from being misaligned, and it is possible to reduce variations due to misalignment between the two. This prevents a drop in crystal impedance and a change in equivalent parallel capacitance during frequency adjustment of the crystal resonator, and maintains good electrical characteristics.

(Effects of the Invention) According to the present invention, a pair of holding members each have a pair of opposing slits, and one pair of opposing slits l- are provided with excitation electrodes on both oil outer peripheries of the piezoelectric piece. are electrically and mechanically connected to each other, and a mask having a through hole at a position corresponding to the excitation electrode is held in the other pair of opposing slits, and an additional film is applied onto the excitation electrode through the through hole of the mask. Since we have adjusted the vibration frequency Fl by forming a film, we can accurately form a film on the excitation electrode at a frequency of 1! Please provide a method for adjusting J.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a holding member attached to a pace for explaining an embodiment of the present invention, FIG. 2 is a diagram showing a crystal piece and a mask plate held on the holding member, and FIG. 3 is a diagram showing a conventional crystal piece. A diagram of a resonator, FIG. 4 is a diagram of a conventional mask, and FIG. 5 is a diagram of a conventional frequency-adjusted crystal resonator. in, lb holding member, 3a13b, 3c, 3d slit, 8 holes, 9 mask plate. 311 Figure 4 5F+

Claims (1)

[Claims] The outer periphery of both ends of a piezoelectric piece provided with an excitation electrode is electrically and mechanically connected to one opposing slit of a pair of holding members each having a pair of opposing slits, and A piezoelectric device characterized in that a mask having a through hole at a position corresponding to the excitation electrode is connected to the slit, and metal particles are attached onto the excitation electrode through the hole of the mask to adjust the vibration frequency. How to adjust the frequency of a vibrator.