JP2003133894A - Quartz vibrator structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the plane dimension of a quartz vibrator structure small by making an internal electrode and an external electrode of a quartz vibrator are connected electrically to each other without providing a through hole to the box body. SOLUTION: By using a frame enclosing the quartz vibrator as a part of the electrode, the internal electrode of the quartz vibrator is made to be connected electrically to the external electrode provided to the box body without using a through hole. Consequently, there is no necessity to use the through hole, so that the plane dimension of the quartz vibrator structure can be made small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal oscillator structure in which a crystal oscillator used as a reference signal source for a timepiece or a mobile communication device is housed. Specifically, the crystal unit and the frame surrounding the crystal unit are integrally formed,
The present invention relates to a crystal unit structure in which an upper housing and a lower housing sandwich the frame portion and hermetically seal the frame portion.

[0002]

2. Description of the Related Art A so-called tuning fork type crystal oscillator having two vibrating legs is widely used as a reference signal source for a timepiece and a mobile communication device. The performance of such a crystal oscillator deteriorates due to friction with air due to vibration, and thus it is necessary to use it in a vacuum atmosphere and used in a state where it is housed in a hermetically sealed case. Figure 1 is the most widely used
It is a cylindrical crystal resonator structure 27 in which the casing as shown in 1 is composed of a metal cylinder. Conduction between the crystal unit inside and the outside is done by two lead wires 2 provided on the bottom surface.
It is done via 9. The lead wire penetrates through the bottom of the housing and connects the inside and the outside of the housing. The penetrating part is filled with glass, and at the same time airtightness is maintained while achieving insulation. Such a cylindrical crystal oscillator structure 27 is used such that the lead wire 29 is connected to the circuit board 31 and then laid down sideways as shown in FIG.
Due to the demand for smaller and thinner watches and mobile communication devices, the crystal unit structure is also required to be thinner, and in response to the request, the height of the parts in the above cylindrical shape is determined by the diameter of the cylinder. Couldn't be smaller. Although various proposals have been made for this problem, in Japanese Patent Laid-Open No. 56-44213, a frame surrounding the crystal unit (hereinafter referred to as "crystal unit frame plate") is manufactured, As shown in FIG. 13, a technique for obtaining a crystal resonator structure by sandwiching the crystal resonator frame plate 1 between an upper housing 7 and a lower housing 9 which are separately manufactured is disclosed. According to this structure, the crystal resonator structure can be thinned. In this publication, the electrode of the internal crystal unit, that is, the internal electrode and the external electrode 21 which is outside the housing and is used for connecting to the circuit board are connected by a through hole 33 formed in the housing.

[0003]

However, in the above-mentioned conventional technique, it is necessary to provide the housing with a through hole.
As a result, there is a problem that the plane size of the crystal unit structure becomes large.

In order to solve the above problems, it is an object of the present invention to provide a crystal resonator structure which can reduce not only the height but also the plane dimension.

[0005]

In order to achieve the above object, according to the present invention, a crystal oscillator frame plate in which a crystal oscillator and a frame portion surrounding the crystal oscillator are integrated, a first casing, In a crystal unit structure including a second case, in which a crystal unit frame plate is sandwiched between the first unit and the second unit and hermetically sealed, a frame upper metal film is provided on the upper surface of the frame unit. In addition, a frame lower metal film is provided on the lower surface of the frame portion, and the upper surface of the frame portion is bonded to the first housing through the conductive upper bonding member, and
The lower surface of the frame portion is joined to the second casing through the conductive lower joining member, and one internal electrode of the crystal unit is
The frame upper metal film, the upper joining member, and the conductor formed on the lower surface of the first housing are electrically connected to one of the external electrodes provided on the upper surface of the first housing, and the other of the crystal units is connected. The internal electrode of is electrically connected to the other external electrode provided on the lower surface of the second housing through the frame lower metal film, the lower bonding member, and the conductor formed on the upper surface of the second housing. It is characterized by being

Further, the crystal unit structure of the present invention is a laminated body including a frame upper metal film, an upper joining member, and a conductor formed on the lower surface of the first housing, a frame lower metal film and a lower portion. It is characterized in that one of the laminated bodies including the joining member and the conductor formed on the upper surface of the second housing is arranged inside and the other is arranged outside.

In the present invention, the internal electrode can be conducted to the outside of the housing without using the through hole by using the frame portion surrounding the crystal unit as a part of the electrode. The planar size can be reduced.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment) FIGS. 1 to 5 are views showing a form of a crystal resonator structure according to the present invention. FIG. 1 is a perspective view of a crystal resonator structure according to the present invention. FIG. 2 is a view of a crystal unit frame plate 1 which is one of the components constituting the crystal unit structure according to the present invention. FIG. 3 is a sectional view of a crystal unit structure according to the present invention. The crystal oscillator structure according to the present invention includes a crystal oscillator frame plate 1 including a crystal oscillator 3 and a frame portion 5 supporting the crystal oscillator 3, and an upper casing 7 and a lower casing that sandwich the crystal oscillator frame plate 1 between the frame portions 5. It consists of body 9. The upper casing 7 and the lower casing 9 are provided with recesses in order to avoid interference with the crystal unit. 4 and 5 are enlarged views of the joint portion between the crystal unit frame plate and the upper casing and the lower casing.
FIG.

The crystal oscillator frame plate 1, the upper casing 7 and the lower casing 9 are each made of quartz and are formed by etching using a liquid in which hydrofluoric acid and an ammonium fluoride aqueous solution are mixed. The crystal oscillator frame plate 1, the upper casing 7, and the lower casing 9 of the present invention are made of quartz having the same crystal orientation. This is to reduce the influence of thermal expansion on the joint. In the crystal resonator structure of the present invention, the width direction of the legs of the crystal resonator 3 coincides with the X-axis direction of the crystal axis of the crystal. The direction in which the legs extend and the direction in which the thickness extends are from the state of being aligned with the Y axis and the Z axis of the crystal axis of the quartz, respectively.
It is a direction rotated by an angle θ with the axis as the axis of rotation. θ is 0
It is 5 °. The crystal oscillator frame plate 1 is composed of the crystal oscillator 3 and the frame portion 5 supporting the crystal oscillator 3 as described above. The frame 5 and the crystal unit 3 are connected at the base of the crystal unit 3. The crystal unit 3 and the frame 5 are integrated, and are formed by etching from a single crystal plate. The crystal oscillator 3 is provided with electrodes for exciting vibration, that is, internal electrodes 11. A frame upper metal film 13 and a frame lower metal film 15 are formed on the upper surface and the lower surface of the frame portion 5, respectively. The purpose of the frame upper metal film 13 is to bond the upper housing 7 to the upper surface of the frame 5 via the upper bonding member 17 and hermetically seal it. The purpose of the frame lower metal film 15 is to bond the lower housing 9 to the lower surface of the frame 5 via the lower bonding member 19 and hermetically seal the lower housing 9. Sn or S is used for the upper joining member 17 and the lower joining member 19.
A low melting point metal such as AuSn alloy containing about 20 wt% of n or a low melting point conductive glass is used.

One of the internal electrodes 11 of the crystal unit is connected to the upper frame metal film 13 on the upper surface side of the crystal unit frame plate 1 and is electrically connected. Further, the frame upper metal film 13 is provided on the upper surface end portion of the upper housing 7 by the upper housing metal film 23 which is a conductor formed in a part of the upper housing 7 via the upper joining member 17. The electrode 21 is electrically connected. As a result, the one internal electrode 11 of the crystal unit 3 is connected to the frame upper metal film 13 and the upper bonding member 1 by the frame upper metal film 13.
External electrode 21 provided at the end of the upper housing 7 via
Has been conducted to. The other internal electrode 11 is connected to the lower frame metal film 15 on the lower surface side of the crystal resonator frame plate 1 and is electrically connected. Further, the frame lower metal film 15
The lower casing metal film 25, which is a conductor attached to the lower casing 9 via the lower joining member 19, is electrically connected to the external electrode 21 provided at the lower end of the lower casing 9. As a result, the other internal electrode 11 of the crystal unit 3
Is electrically connected to the external electrode 21 provided at the end of the lower housing 9 through the frame lower metal film 15 and the lower joining member 19.

In order to maintain the strength of the joint portion, it is desirable to widen the joint range between the upper joint member 17 and the lower joint member 19 as shown in FIG. 4, but since the upper joint member 17 and the lower joint member 19 are used as electrodes. The parallel capacitance C0 between the electrodes increases. Increasing the parallel capacitance C0 increases the capacitance ratio γ = C0 / C1 which is the ratio of the parallel capacitance C0 to the series capacitance C1.
This narrows the variable range of the oscillation frequency in the self-excited oscillation circuit. In order to improve this point, as shown in FIG. 5, one side may be inside and the other side may be outside so that the upper and lower joints of the crystal resonator frame plate do not face each other. The shapes of the frame upper metal film 13 and the frame lower metal film 15 in this case are shown in FIG. The frame upper metal film 13 is arranged inside and the frame lower metal film 15 is arranged outside. The upper joining member 17 and the lower joining member 19 are the upper frame metal film 13 and the lower frame metal film 1, respectively.
It has the same shape as that of the frame portion of No. 5.

The positions of the external electrodes 21 provided on the upper casing 7 and the lower casing 9 can be freely set. The external electrodes 21 of the upper housing 7 and the external electrodes 21 of the lower housing 9 may be located at both ends of the crystal resonator structure as shown in FIG. 7, or as shown in FIG. It can also be one end of the structure. Further, as shown in FIG. 9, the external electrode 21 may be located at the center of the crystal resonator structure. Furthermore, as shown in FIG.
Can be provided on the entire upper surface of the upper housing 7 and the entire lower surface of the lower housing 9.

In the present embodiment, an example in which quartz is used for the upper and lower casings has been shown, but it is important to utilize the frame portion for conduction between the internal electrode and the external electrode, and the problem of the present invention is to be solved. To solve the problem, it is not always necessary to use quartz, and it is clear that the same effect can be obtained by using ceramics such as alumina and zirconia or glass ceramics. In addition, although a tuning fork type crystal oscillator is shown as an example in the present embodiment, it is clear that the present invention is effective as long as it is driven by using two electrodes such as an AT plate.

[0015]

As described above, according to the crystal resonator structure of the present invention, the conduction between the internal electrode and the external electrode can be performed without providing the through hole, so that the planar dimension can be reduced accordingly. There is. Further, since the position of the external electrode is not restricted by the through hole, there is an effect that the position of the external electrode can be freely set. Further, there is an effect that an increase in parallel capacitance between the electrodes of the crystal unit can be suppressed and the frequency variable range can be kept wide.

[Brief description of drawings]

FIG. 1 is a perspective view of a crystal unit structure according to the present invention.

FIG. 2 is a diagram of a crystal oscillator frame plate that is one of the components that constitute the crystal oscillator structure according to the present invention.

FIG. 3 is a cross-sectional view of a crystal unit structure according to the present invention.

FIG. 4 is a cross-sectional view of a joint between a crystal unit frame plate and an upper casing and a joint between a crystal unit frame plate and a lower casing in a crystal unit structure according to the present invention.

FIG. 5 is a cross-sectional view of a joint between a crystal unit frame plate and an upper casing and a joint between a crystal unit frame plate and a lower casing in a crystal unit structure according to the present invention.

FIG. 6 is a diagram of a crystal oscillator frame plate that is one of the components that constitute the crystal oscillator structure according to the present invention.

FIG. 7 is a diagram of a crystal resonator structure according to the present invention, showing the positions of external electrodes.

FIG. 8 is a diagram of a crystal resonator structure according to the present invention, showing the positions of external electrodes.

FIG. 9 is a diagram of a crystal resonator structure according to the present invention, showing the positions of external electrodes.

FIG. 10 is a diagram of a crystal resonator structure according to the present invention,
It is a figure which shows the position of an external electrode.

FIG. 11 is a view showing a cylindrical crystal oscillator structure which is a conventional crystal oscillator structure.

FIG. 12 is a view showing a mounted state of a cylindrical crystal oscillator structure which is a conventional crystal oscillator structure.

FIG. 13 is a diagram showing a conventional crystal resonator structure.

[Explanation of symbols]

1 Crystal oscillator frame plate 3 Crystal unit 5 frame 7 Upper case 9 Lower case 11 internal electrodes 13 Upper frame metal film 15 Lower frame metal film 17 Upper joining member 19 Lower joining member 21 External electrode 23 Upper case metal film 25 Lower case metal film 27 Cylindrical crystal unit structure 29 lead wire 31 circuit board 33 through hole

Claims (2)

[Claims] 1. A crystal resonator frame plate comprising a crystal resonator and a frame portion surrounding the crystal resonator, a first casing, and a second casing. In a quartz resonator structure sandwiched between the first casing and the second casing and hermetically sealed, a frame upper metal film is provided on an upper surface of the frame portion and a frame lower metal film is formed on a lower surface of the frame portion. And an upper surface of the frame portion is joined to the first casing through an upper joint member having conductivity, and a lower surface of the frame portion is joined through a lower joint member having conductivity. One of the internal electrodes of the crystal unit, which is joined to the second casing, is connected to the frame upper metal film, the upper joint member, and the conductor formed on the lower surface of the first casing through the conductor. One of the external electrodes provided on the upper surface of the first housing is electrically connected, and the other internal electrode of the crystal unit is connected to the bottom of the frame. It is electrically connected to the other external electrode provided on the lower surface of the second housing through the partial metal film, the lower bonding member, and the conductor formed on the upper surface of the second housing. Characteristic crystal oscillator structure. 2. A laminated body including the frame upper metal film, the upper joining member, and a conductor formed on the lower surface of the first casing, the frame lower metal film, the lower joining member, and the first lower member. 2. The crystal resonator structure according to claim 1, wherein one of the laminated bodies made of a conductor formed on the upper surface of the second casing is arranged inside and the other is arranged outside.