JP2003283293A - Quartz vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface mounting vibrator in which an other terminal part of the quartz element is surely separated from a base surface and the phase noise characteristics are improved. <P>SOLUTION: The quartz vibrator is composed in that both sides of an end section of a quartz element whose exciting electrodes are extended out to drawing out electrodes, are fixed on inside bottom plane of a case main body by electro-conductive glue. A projection is provided between a end part of the quartz element and the base and an end face of the quartz element is projected from the projection. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal resonator for surface mounting (hereinafter referred to as a surface mounting resonator) in the technical field of industry, and particularly to a surface mounting resonator from which noise is removed.

[0002]

(Background of the Invention) A surface mount oscillator is incorporated in an oscillator or the like as a frequency and time reference source, and since this type is small and lightweight, it is used for various portable electronic devices. Widely used in equipment. in recent years,
The standards are becoming more stringent, and there are demands for surface mount oscillators that have low noise components and particularly good phase noise characteristics.

(Example of Prior Art) FIG. 6 is a cross-sectional view of a surface mount oscillator for explaining an embodiment of the present invention. The surface mount oscillator is generally composed of a container body 1 and a crystal piece 2.
The container main body 1 is made of laminated ceramics and has a recess having stepped portions formed on both end sides. Further, the step portion on the one end side has a pair of crystal connection terminals 3 and is electrically connected to a mounting terminal on the bottom surface (not shown) through the laminated surface and the side surface. The crystal piece 2 has the excitation electrodes 4 on both main surfaces, and the extraction electrodes 5 are extended to both sides of one end (FIG. 7). Then, both sides of the extended one end of the extraction electrode 5 are fixed to the crystal connection terminals 3 on the stepped portion by a conductive adhesive 6 to electrically and mechanically connect.

Normally, a conductive adhesive 6 is applied (undercoating) on the crystal connecting terminals 3 provided on the step portion on one end side of the container body 1, and both end portions of the crystal piece 2 are stepped on one end side. The other end is placed on the step on the other end side. Then, the conductive adhesive 6 is applied (overcoating) on the surface of one end of the crystal piece 2 and heat-cured by high temperature heating. As a result, both ends of the crystal piece 2 are fixed on the crystal connection terminal 3. Reference numeral 7 in the figure is a cover.

[0005]

Problems to be Solved by the Invention (Problems of Prior Art)
However, the surface mount oscillator having the above configuration has a problem that, for example, noise is superimposed on the vibration frequency during the operation of a mobile device (for example, a mobile phone) to deteriorate the phase noise characteristic. That is, the other end of the crystal piece 2 is placed in contact with or close to the step on the other end (FIG. 8). Therefore,
For example, when a vibration source such as a motor is built in a portable device, a low-frequency vibration sound propagates to the other end of the crystal blank 2 and is superimposed on the vibration frequency. This deteriorates the phase noise characteristic.

From the above, in order to prevent the other end of the crystal piece 2 from coming into contact with or approaching the other end, for example, a spacer (not shown) is interposed between the other end of the crystal piece 2 and the step, and the conductive bonding is performed. After the agent 6 is cured, it is removed. Alternatively, there is a proposal to lift the other end side of the crystal piece 2 by utilizing the contracting force when the conductive adhesive 6 is cured (Patent No. 2668585).
issue).

In the former case, however, it takes a lot of time to dispose and remove the spacer, and the smaller the size, the lower the workability. In the latter case, the conditions such as the coating amount and the position of the conductive adhesive 6 are difficult, and there is a problem of lack of repeatability.

(Object of the Invention) It is an object of the present invention to provide a surface mount oscillator in which the other end portion of the crystal element is surely floated from the surface of the base to improve the phase noise characteristic.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a protrusion is provided between one end of a crystal piece from which an extraction electrode extends and a bottom surface inside a container, and one end surface of the crystal piece is projected from the protrusion to provide conductivity. Fixing with an adhesive is a basic solution.

[0010]

In the present invention, since the projection is provided between the one end of the crystal piece and the base, the other end is formed as the base by the curing shrinkage of the conductive adhesive interposed between the one end surface of the crystal piece and the projection. Can be floated from the bottom. That is, with the protrusion as a fulcrum, a rotational moment due to curing shrinkage of the conductive adhesive acts,
The other end floats. An embodiment of the present invention will be described below.

FIG. 1 is a sectional view of a surface mount oscillator for explaining an embodiment of the present invention. It should be noted that the same parts as those of the prior art example are given the same reference numerals, and the description thereof will be simplified or omitted. The surface mount oscillator is the container main body 1 having the recess as described above.
Both ends of the crystal piece 2 are placed on the steps on both ends of the, and the conductive adhesive 6 is applied and fixed to both sides of the one end to electrically and mechanically connect to the crystal connection terminal 3. .

Further, in this embodiment, as shown in the plan view of FIG. 2, a linear projection 8 is provided on the tip side of the crystal connecting terminal 3. The protrusion 8 is made of a metal or an insulator, and is integrally formed when the crystal connection terminal 3 is printed and baked. The dashed-dotted line in the figure is the crystal piece 2.

In such a device, first, the conductive adhesive 6 including the projections 8 is undercoated on the step portion on the one end side where the crystal connection terminals 3 are provided. Then, as shown in FIG. 3 (a), one end of the crystal piece 2 from which the extraction electrode 5 is extended is a step on one end side, and the other end of the crystal piece 2 is a step on the other end side. Place it. In this case, the projection 8 with one end surface of the crystal piece 2 as a fulcrum
Project from. In this state, the other end of the crystal piece 2 is almost in contact with the surface of the stepped portion and is inclined to the right when viewed from one end.

Next, a conductive adhesive 6 is overcoated on both sides of one end of the crystal blank 2 from the upper surface, and heated to heat cure. In this case, the conductive adhesive 6 shrinks due to thermosetting. Then, due to contraction of the conductive adhesive 6 which is particularly undercoat interposed between the one end surface of the crystal piece 2 and the protrusion 8, an arrow P. As indicated by Q, one end of the crystal piece 2 is pulled down and the other end is pulled up.

In short, a rotational moment acts on the projection 8 as a fulcrum, one end is pulled down and the other end is pulled up. As a result, the other end of the crystal piece 2 is lifted from the surface of the step. Therefore, with such a configuration, for example, the vibration sound of the motor is prevented from propagating to the crystal piece 2 and the phase noise characteristic is maintained excellently.

[0016]

[Other Matters] In the above-mentioned embodiment, the conductive adhesive 6 has two steps of undercoating and topcoating, but it is of course applicable to only the undercoating. Further, even if only the top coat is used, any one can be applied as long as the conductive adhesive 6 penetrates into the gap between the crystal piece 2 and the step portion. Further, although the protrusion 8 is provided on the crystal connecting terminal 3, the present invention is not limited to this, and may be provided between the crystal connecting terminals 3, for example, and may be provided according to the gist of the present invention.

Further, the surface mount oscillator has been described above,
For example, the same can be applied to the case where an oscillator is configured by accommodating IC chips between the steps on both ends (FIG. 4). Then, although both ends of the crystal piece 2 are placed and fixed on the stepped portion, the same can be applied when the crystal piece 2 is fixed on the inner bottom surface of the container body without the stepped portion (FIG. 5). In the claims, the inner bottom surface includes the surface of the stepped portion.

Although the container body 1 is concave, it may be a flat plate having a mounting electrode on the back surface and is covered with a concave cover. Further, although the crystal piece 2 has a flat plate shape, for example, both ends may beveled or have a convex shape.

[0019]

According to the present invention, a protrusion is provided between one end of the crystal piece from which the extraction electrode is extended and the inner bottom surface of the container body, and one end surface of the crystal piece is projected from the protrusion by a conductive adhesive. Since it is fixed, the other end of the crystal piece can be surely floated from the surface of the base to provide a surface mount oscillator having good phase noise characteristics.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a surface mount oscillator for explaining an embodiment of the present invention.

FIG. 2 is a plan view of a container body for explaining an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a surface mount oscillator for explaining the operation of one embodiment of the present invention.

FIG. 4 is a diagram of a surface mount oscillator for explaining another application example of the present invention.

FIG. 5 is a diagram of a surface mount oscillator for explaining another application example of the present invention.

FIG. 6 is a cross-sectional view of a surface mount oscillator for explaining a conventional example.

FIG. 7 is a plan view of a crystal piece for explaining a conventional example.

FIG. 8 is a cross-sectional view of a surface mount oscillator for explaining the problems of the conventional example.

[Explanation of symbols]

1 container body, 2 crystal piece, 3 crystal connection terminal, 4 excitation electrode, 5 extraction electrode, 6 conductive adhesive, 7 cover, 8 protrusion, 9 IC chip.

Claims (2)

[Claims] 1. A crystal unit in which both ends of a crystal piece in which an extraction electrode extends from an excitation electrode are fixed to an inner bottom surface of a container body by a conductive adhesive, wherein one end of the crystal piece and the base are provided. A crystal resonator, wherein a protrusion is provided between the crystal piece and one end surface of the crystal piece so as to protrude from the protrusion. 2. A crystal resonator provided on the crystal connection terminal, wherein the protrusion is electrically connected to the extraction electrode.