JPH02291710A - Crystal vibrator - Google Patents

Abstract

PURPOSE:To prevent the frequency change due to the heat expansion by fixing a holding crystal piece to a base board in the direction orthogonal to the direction where the holding crystal piece is fixed to a vibrator crystal piece. CONSTITUTION:A holding crystal plate 11 and a vibrator crystal piece 4 are cut in the same direction for AT cut and in the rectangular cutting forms. The fixing direction (X-X line direction) between a base board 10 and the piece 11 is set orthogonal to the fixing direction (Z-Z line direction) between the piece 11 and the piece 4. The piece 11 is larger than the piece 4 in the same direction and therefore the distortion of the board 10 is absorbed for reduction of the stress of the piece 4. In such a constitution, a crystal vibrator is free from the frequency change due to a heat expansion error.

Description

Detailed Description of the Invention (Field of Application of the Invention) The field of the invention is a crystal resonator as an oscillator, a filter element, etc., and in particular, the field of application is a crystal resonator as an oscillator, a filter element, etc. This invention relates to a thin crystal oscillator with improved protection.

(Background of the Invention) Crystal resonators are frequently used in various electronic devices as frequency and time reference sources, for example, as oscillators.

In recent years, with the trend of electronic devices, small and thin (
(Suitable for surface mounting), there is a desire for a crystal resonator that prevents frequency changes due to thermal expansion (Reference Publication: Japanese Utility Model Publication No. 82-44580).

<<Prior Art>> FIG. 2 is a diagram of a crystal resonator illustrating a conventional example of this type.

The crystal resonator consists of a metal base 2 from which a pair of lead terminals 1 protrude, a holding crystal piece 3, and a vibrator crystal piece 4. The holding crystal blank 3 has through holes 5 formed at both ends in the longitudinal direction, and metallized lightning poles 6 formed in the holes. and,
The lead terminal 1 is fitted 17 into the through hole 5 and connected to the Mekrise electrode 6, and is fixed on the base surface. The vibrator crystal piece 4 has, for example, a rectangular shape elongated in the X-axis direction, and extends from the vibrating electrodes 7 on both main surfaces to the outer periphery of both ends in opposite directions. The outer periphery of both ends of the surface facing the holding crystal plate 3 is fixed onto the metallized electrode using, for example, a conductive adhesive. However, depending on the thickness of the conductive adhesive (and metallized electricity IV!), a gap is created between the opposing surfaces of the holding crystal plate 3 and the vibrator crystal piece 4, so that the excitation of the vibrator crystal piece 4 is not inhibited. shall be taken as a thing.

In this type of device, since the crystal piece 4Ie for the oscillator is directly fixed to the holding crystal plate 3 using conductive adhesive, the holding sabot 9 may be removed as shown in FIG. 3, for example. Can you reduce the height dimension? Furthermore, since the holding crystal plate 3 and the vibrator crystal piece 4 are made of the same material, they have the same coefficient of thermal expansion. , 17 Therefore, no stress is generated in the vibrator crystal piece 4 due to the difference in thermal expansion coefficient with the holding system. Then, it is possible to prevent frequency changes caused by stress sensitivity characteristics and obtain a frequency-temperature characteristic (see FIG. 4) that is, for example, a cubic curve, which is inherent to a crystal resonator.

Furthermore, damage to the vibrator crystal plate 4 due to stress that occurs in extreme cases can also be prevented.

(Problems with Prior Art) j7 However, in the crystal resonator having the above configuration, the outer peripheral portions of both ends of the holding crystal plate 3 are fixed by lead wires. Therefore, the holding crystal plate 3 is forced by the thermal expansion of the base,
Expansion and contraction, especially in the longitudinal direction, associated with the natural coefficient of thermal expansion is inhibited (ie, stress is created). From such a thing,
In reality, the resonator crystal piece 4 fixed to the holding crystal plate 3 is subject to stress, particularly in the longitudinal direction, which causes frequency changes and impairs the original temperature characteristics.

(Objective of the Invention) An object of the present invention is to provide a crystal resonator that is suitable for miniaturization, prevents frequency changes due to thermal expansion, and has good vorticity characteristics.

(Solution Means and Effects) The solution of the present invention is that the fixing direction of the base (pace) and the holding crystal piece is orthogonal to the fixing direction of the holding crystal piece and the vibrator crystal piece. With this solution, the fixing direction of the resonator crystal piece and the holding crystal plate is a free end, which is perpendicular to the fixing direction of the base and the holding crystal piece, so there is an effect of preventing the generation of stress in this direction. . Examples of the present invention will be described below.

(Embodiment) FIG. 1 is a diagram of a crystal resonator explaining an embodiment of the present invention, in which (a) is a perspective view, and (b) is a Z-
It is a sectional view on the Z line. Incidentally, the same parts as in the previous conventional example are given the same numbers and the explanation thereof will be simplified.

The crystal resonator is composed of, for example, a base 10 made of ceramics which becomes a part of the container, a holding crystal plate 11, and a vibrator crystal plate 4. The holding crystal plate 11 and the vibrator crystal piece 4 are both cut in the same direction as an AT cut, and have a rectangular shape. Then, the longitudinal direction is the crystal axis (x% y%
The X axis of Z), the short direction is the Z' axis, and the thickness direction is the y' axis. The holding crystal plate 11 is made larger in all directions than the vibrator crystal piece 4. Then, /)-7 etching is performed on one main surface side to a depth of 5IrIff1 excluding both ends.
The following holes 12 are formed in a concave shape.

In such a device, the holding crystal plate 11 is fixed to the base 10 at both ends in the lateral direction on the other main surface side, and at the central portion in the longitudinal direction, to the base 10 with an adhesive 13. The vibrator crystal piece 4 is held in the longitudinal direction (and the transverse direction) by the holding crystal piece 11
The outer peripheries of both ends of the extraction electrode 8 extending from the excitation electrode 7 are fixed onto the legs of the holding crystal plate 11 using a conductive adhesive 14. That is, a direction perpendicular to the direction in which the base 10 and the holding crystal piece 11 are fixed (the direction of the X-X line in the figure) and the direction in which the holding crystal piece 11 and the vibrator crystal piece 4 are fixed (the direction of the Z-Z line in the same figure). Make it. Note that a conductive path (not shown) connected to the vibrator crystal piece 4 is formed on the base 10 and the holding crystal plate 11.

Then, external connection terminals (not shown) are formed on the surface of the container of the base by, for example, through-hole processing, and a cover is further placed on the container for surface mounting.

In such a device, the concave portion 12 of the holding crystal plate 11 creates a gap between the surfaces facing the vibrator crystal plate piece 4, thereby ensuring the excitation of the vibrator crystal piece 4. Since only the transverse direction of the holding crystal plate 11 is fixed to the base 10, the longitudinal direction becomes a free end. Therefore, in the longitudinal direction, it is able to expand and contract with respect to heat, and stress does not occur. Further, the vibrator crystal piece 4 has its longitudinal direction aligned with the same direction as the holding crystal piece 11, and its both ends are fixed. Therefore, the expansion and contraction of the vibrator crystal piece 4 in the longitudinal direction is affected by the holding crystal piece 11, but since both are made of the same material and have the same coefficient of thermal expansion, no stress due to heat is substantially generated. In addition, in this embodiment, the short side direction of the holding crystal plate 11 is the fixed end and l7.
Although there is some influence (occurrence of scratches and scratches), the holding crystal plate 1
1 is larger than the resonator crystal piece 4 in the same direction, so
The stress on the vibrator crystal piece 4 is reduced by absorbing the distortion of the substrate 10. For this reason, the crystal resonator having this configuration prevents frequency changes caused by the difference in thermal expansion, so that the temperature characteristics of the crystal piece 4 for the resonator, which form a cubic curve, can be maintained well.

(Other matters) In the embodiment described above, both ends of the holding crystal plate 11 in the transverse direction were fixed to the base 10. Moving the line in the longitudinal direction? 1. Even if that is the case, the effect can be fully expected.Also,
The vibrator crystal piece 4 is fixed to the holding crystal plate 11 at both end outer circumferential parts where the extraction electrode 8 extends, but for example, the central part of the outer circumferential part at both ends is fixed at points, and both transverse ends are free ends. It is also possible to avoid stress in this direction. Furthermore, although the adhesive 13 is simply applied between the base 10 and the holding crystal plate 11, for example, a groove or the like is provided around the adhesive application area to prevent the application area from spreading due to the adhesive flowing out. You can also do this.

In addition, although the vibrator crystal piece 4 has a rectangular shape elongated in the X-axis direction, it may be a rectangular shape elongated in the Z'-axis direction, or it may be square or disc-shaped. It can be implemented regardless of the Although the resonator crystal piece 4 is an oscillator, it can also be applied to an MCF or the like in which a plurality of pairs of electrodes such as so-called input/output electrodes and a common electrode are formed using, for example, multiple modes.

Furthermore, although the base 10 is a part of the ceramic container, it is not limited thereto, and may of course be made of a metal base, and the present invention may be modified as appropriate without departing from the spirit thereof. It is.

(Effects of the Invention) In the present invention, the fixing direction of the base and the holding crystal piece is orthogonal to the fixing direction of the holding crystal piece and the vibrator crystal piece, so that frequency changes due to thermal expansion can be prevented. We can provide crystal resonators that have good temperature characteristics and are suitable for downsizing.
Its utility value is enormous.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram of a crystal resonator illustrating an embodiment of the present invention, in which (a) is a perspective view, and (b) is a cross-section taken along X1-X-ray 12. It is a diagram. FIG. 2 is an exploded perspective view of a crystal resonator to explain a conventional example, FIG. 3 is a perspective view of a crystal resonator to explain another conventional example, and FIG.
The figure is a frequency-temperature characteristic diagram of a crystal resonator. No.lm

Claims (1)

[Claims] A base, a holding crystal plate having a recess formed by half etching, and a resonator crystal plate having an outer circumference of an end thereof held on the leg of the recess, and fixing the holding crystal piece to the base. A crystal resonator characterized in that the direction and the fixing direction of the holding crystal piece and the vibrator crystal piece are orthogonal to each other.