JPS6317247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the support structure of a piezoelectric vibrator vibrating in a longitudinal vibration mode, a bending vibration mode, and a contour-sliding vibration mode, particularly a line-supported piezoelectric vibrator.

Piezoelectric resonators such as crystal resonators and piezoelectric ceramic resonators take advantage of the high Q and high stability characteristics of mechanical resonators, and are often used as reference frequency oscillation elements and wave transmitter elements in various communication devices. In particular, crystal oscillators have been widely used as oscillating elements for watches in recent years due to the advent of artificial quartz, coupled with the stability of their resonant frequencies, contributing to the high performance and economicalization of not only communication devices but also various consumer devices. ing.

FIG. 1 shows a schematic structural diagram of a conventional piezoelectric resonator, particularly a line-supported X-cut longitudinal vibrating type crystal resonator. In the figure, a crystal oscillator piece 1 is supported by electrodes 2 formed on both sides of the crystal oscillator piece and support wires 3' connected to each by soldering or the like.
Further, the support wire 3' is connected to a terminal 5 provided on the substrate 4 to support the crystal resonator piece.

In the X-cut longitudinal oscillation type crystal resonator shown in Figure 1, in order to obtain the high Q and high stability characteristics that are the characteristics of a crystal resonator, solder balls, etc., shown as 6 in the figure, are attached to the support wires of the crystal resonator pieces. We are trying to stabilize the characteristics.
However, it is very difficult to set the mounting position of the solder ball 6, and if the setting is not appropriate, the resonance resistance will increase significantly at a certain temperature when the ambient temperature of the crystal resonator changes, and the resonance frequency will also change at this temperature. causes abnormal changes. This is support line 3'
Since the distance from the attachment point with the electrode 2 to the position of the solder ball 6 is long, the resonant frequency of the bending system of the support wire almost matches the resonant frequency of the crystal resonator piece at a certain temperature, so the vibration energy of the crystal resonator is reduced. This occurs because a portion of this is transmitted to the support line.

For this reason, in manufacturing the crystal resonator shown in Figure 1, the resonance resistance is adjusted while changing the ambient temperature of the crystal resonator, that is, the position of the solder balls is set, and it is confirmed that the above-mentioned abnormal phenomenon does not occur. It requires a lot of time to manufacture.

On the other hand, with the remarkable development of semiconductor components in recent years, the use of ICs in communication devices has progressed, and the parts used have become smaller and smaller.
In particular, the height of mounted components is required to be equivalent to that of the ICs, LSIs, etc. used, and there is also a strong demand for miniaturization of crystal resonators.

In the conventional structured crystal resonator shown in Fig. 1,
Since the crystal resonator piece 1 has a three-dimensional structure arranged perpendicularly to the substrate 4, the width W of the crystal resonator piece 1 is made smaller in order to lower the overall height including the case of the crystal resonator (not shown). There is a need.

On the other hand, the equivalent inductance L of a longitudinally vibrating X-cut crystal resonator is determined by the dimensions of the crystal resonator, as shown in equation 1.

L=K _L l・t/W [H] ...(1) K _L : Inductance constant (9.5 to 10.1) [H/mm] l: Length of crystal resonator [mm] W: Width of crystal resonator [mm] t: Thickness of the crystal resonator [mm] As can be seen from equation (1), the equivalent inductance L increases as the width W of the crystal resonator piece decreases. Since the equivalent inductance of a crystal resonator is determined by the design of the device, etc., when the width W is made small, the thickness t needs to be made small to keep the equivalent inductance constant. Note that the length l of the crystal oscillator is related to the frequency, so it cannot be changed.

If the entire crystal resonator including the case is lowered and made smaller using the method described above, the crystal resonator piece 2 becomes smaller in width and thinner, which reduces the mechanical strength of the crystal resonator piece. Manufacturing yields decrease due to breakage during polishing, frequency adjustment, and support wire attachment of crystal resonator pieces.

As explained above, the line-support type piezoelectric vibrator having the conventional structure is complicated to manufacture, and has drawbacks such as a reduction in manufacturing yield when miniaturization is promoted.

The present invention has been made in view of the above-mentioned drawbacks, and involves inserting a wire-supported piezoelectric vibrator piece into a hole in the center of a rectangular support frame having a hole in the center. After the wire is fixed to the metal film conductor formed on the support frame, the metal film conductor of the support frame mentioned above is used to make a fixed connection to the external output terminal attached to the board. In order to stabilize the characteristics without using solder balls to prevent resonance of the support wire, and to facilitate manufacturing, the substrate and the vibrator piece are arranged in parallel so that their surfaces face each other. Achieves a flat structure,
The present invention provides a piezoelectric vibrator that is small and easy to manufacture using a piezoelectric vibrator having the same dimensions as the conventional piezoelectric vibrator.

Embodiments of the piezoelectric vibrator according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a perspective view showing an embodiment in which the present invention is applied to an X-cut longitudinally vibrating crystal resonator as in FIG. 1. In the figure, 1 is a rectangular crystal resonator piece with electrodes 2 formed on both sides (only one side is shown in the figure), 3 is a support line made of a straight conductive metal thin wire, and each support line 3 is on one side. The ends of the crystal resonator piece 1 are connected to the electrodes 2 on both sides at the center in the longitudinal and width directions using a bonding material such as solder, and the other end is attached to a support frame made of the ceramic material of the present invention. A metal film conductor 8 is formed as a conductive film pattern on the end face of 7 by vapor deposition, sputtering, etc.
It is joined and fixed with solder, etc. In this case, one side of the crystal resonator piece 1 is inserted into the hole 9 in the internal space of the support frame 7 in a non-contact state.

Further, the support frame 7 to which the crystal resonator piece 1 is attached has an external extraction terminal 5 provided through the substrate 4 and a metal film conductor 8 of the support frame 7 described above.
It is fixedly attached to one end using a conductive bonding material such as solder. At this time, one electrode surface of the crystal resonator piece 1 and the surface of the substrate 4 are positioned so as to face each other, that is, to be substantially parallel to each other.

FIG. 3 is a front view seen from the direction of arrow A in FIG. 2 in order to make the above explanation easier to understand. The metal film conductor 8 of the support frame 7 is used not only to mechanically hold the support wire 3 of the crystal resonator piece 1 and to fix the external lead terminal 5 and the support frame 7, but also to apply an electric field to the crystal resonator piece 1 from the outside. Since it plays the role of electrical connection for applying voltage, it is made of a good conductor made of silver, gold, etc.

The crystal resonator according to the present invention shown in FIG. 2 does not use solder balls as shown in FIG. 1.
As is clear from the figure, since the support wire 3 has a linear shape, there is no bending vibration of the support wire caused by bending the support wire, and furthermore, the support wire 3 is fixed to the crystal resonator electrode 2. The length of the support wire 3 between the fixed portion and the metal film conductor 8 of the support frame 7 can be shortened, and the resonant frequency of longitudinal vibration, torsional vibration, etc. of the support wire can be made lower than the resonant frequency of the contour piezoelectric vibrator. This is because it can be made sufficiently high.

As a result, it is possible to suppress the increase in resonant resistance at a certain temperature and the occurrence of abnormal changes in resonant frequency, which are observed in wire-supported piezoelectric vibrators with conventional structures, without using solder balls, and eliminate the resistance adjustment process. Manufacturing can be simplified.

Figure 4 shows the temperature characteristics of the resonant resistance and resonant frequency for a crystal resonator with a conventional structure, curve A without solder balls, curve B with solder balls, and curve C for the crystal resonator of the present invention. . B in the figure indicates an abnormal change in resonance resistance and resonance frequency due to bending system resonance of the support wire.

Furthermore, by using the support frame of the present invention, the substrate 4 and the crystal resonator piece 1 can be arranged parallel to each other. A piezoelectric vibrator can be easily realized with good manufacturability.

Although the embodiments of the X-cut longitudinal oscillation type crystal resonator have been described above, the present invention is applicable to line-supported DT cut contour slip crystal resonators, CT cut contour slip crystal resonators, as well as longitudinal resonators using piezoelectric ceramics. The same structure can also be applied to a bimorph bending vibrator. Furthermore, the present invention is not limited to the above-described embodiments; for example, the support frame may be made of an electrically insulating material such as glass material in addition to ceramics, and the surface to be joined to the substrate may be attached with an adhesive, for example, metallized and bonded with solder or the like. Alternatively, the support frame may be made mainly of metal, and an insulating plate or an insulating layer may be integrated on the end face, and a conductive film pattern may be formed thereon.
In this way, attachment to the board can be ensured. In addition, the conductive film pattern etc. can also be formed by printing and baking. In addition, during the description of the present application, in order to make the description easier to understand, parts other than the main parts, such as the case attached to the substrate, are omitted.

As described above, the piezoelectric vibrator of the present invention can be used to integrate various devices into ICs,
By simplifying the manufacturing process, a small piezoelectric vibrator compatible with LSI can be made economically and with high performance, and its industrial value is enormous.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of the main parts of a conventional longitudinally vibrating crystal resonator, FIG. 2 is a schematic perspective view showing only the main parts of an embodiment of the longitudinally vibrating crystal resonator according to the present invention, and FIG. A view taken in the direction of arrow A in Fig. 2, and Fig. 4 are characteristic diagrams showing the temperature change characteristics of the resonant resistance and resonant frequency of the crystal resonator of the conventional structure with and without solder balls, and of the crystal resonator of the present invention. be. In the figure, 1 is a crystal resonator piece, 2 is an electrode, 3, 3'
is the support line, 4 is the board, 6 is the solder ball, 7 is the support frame,
Reference numeral 8 indicates a metal film conductor, and reference numeral 9 indicates a hole, and the same parts are given the same reference numerals throughout the figures.

Claims (1)

[Scope of Claims] 1. A rectangular piezoelectric vibrator piece with electrodes formed on both sides, and a conductive metal embedded in each of the electrodes at the center of the piezoelectric vibrator piece in the length direction and width direction. A support line made of a thin wire, and a frame-shaped support frame into which the piezoelectric vibrator piece is inserted, and the ends of the support wire are bonded and supported to conductive film patterns formed on the end faces of the frame shape. and a substrate to which the support frame is attached, the piezoelectric vibrator comprising one electrode surface of the piezoelectric vibrator piece and a surface of the substrate facing each other. 2. The piezoelectric vibrator according to claim 1, wherein the support frame is made of an insulator. 3. The piezoelectric vibrator according to claim 1, wherein the support frame is bonded and attached to a conductive film pattern of the support frame and a terminal provided on the substrate, respectively. 4. The piezoelectric vibrator according to claims 1 and 2, wherein the support frame is fixed to the substrate using an adhesive or the like.