JP2004363936A - Surface-mounted crystal vibrator and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounted crystal vibrator capable of suppressing a decrease in support loss resulting from reduction in the size of a crystal piece. <P>SOLUTION: Projection type conductive adhesives 7a and 7b are built on the crystal piece 9 and then the spread of the conductive adhesives is prevented on surfaces coming into contact with lead-out electrodes 5a and 5b to suppress the support loss. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface-mount type crystal unit that can be mounted on a surface of a printed wiring board, for example.
[0002]
[Prior art]
[Patent Document] JP-A-2002-094352
2. Description of the Related Art In recent years, surface mount type crystal units have been widely used in various electronic devices such as mobile communication devices. The above patent document discloses a structure of a quartz oscillator.
3A and 3B are views showing the internal structure of a conventional surface-mount type crystal unit. FIG. 3A is a top view of the crystal unit, and FIG. Are shown respectively. The cross-sectional view shown in FIG. 2B is a cross-sectional view of the crystal resonator taken along the alternate long and short dash line shown in FIG.
[0003]
As shown in FIGS. 3A and 3B, a conventional surface mount type crystal unit (hereinafter, simply referred to as a “crystal unit”) includes a crystal piece inside an airtight container including a container body 100 and a lid 108. 107 is accommodated.
The container body 100 is formed of, for example, ceramic, and has convex portions 102 and 103 on both sides of the bottom surface inside the container body.
[0004]
The protruding portion 102 is a portion where an extraction electrode to which the excitation electrodes 107a and 107b attached to the crystal piece 107 are connected is formed, and is divided into two regions by a gap G provided at a central portion thereof. The extraction electrodes 105a and 105b are formed in the respective regions. Conductive adhesives 106a and 106b are used to connect the extraction electrodes 105a and 105b to the electrodes 107a and 107b of the crystal piece 107.
[0005]
The projection 103 serves as a receiving surface for holding the other end of the crystal piece 107 that is not connected to the extraction electrodes 105a and 105b when connecting the electrodes 107a and 107b of the crystal piece 107 and the extraction electrodes 105a and 105b. Is provided.
Hereinafter, in the present specification, the protrusion 102 on which the extraction electrode connected to the electrodes 107a and 107b of the crystal blank 107 is formed is referred to as a “protrusion for extraction electrode”, and the other end of the crystal blank 107 is held. The protruding portions 103 are distinguished by notation as “mounting protruding portions”.
[0006]
On the outer bottom surface of the container body 100, for example, four electrode terminals 109, 109,... Are provided at four corners, and two electrode terminals 109, 109, among these four electrode terminals 109, 109,. Reference numeral 109 is connected to the extraction electrodes 105a and 105b in the container body 100 by the conductive lines 110 and 110, respectively.
[0007]
[Problems to be solved by the invention]
When the electrodes 107a and 107b of the crystal blank 107 and the extraction electrodes 105a and 105b are connected to each other in the manufacture of the above-described conventional crystal resonator, conductive bonding is performed on the respective extraction electrodes 105a and 105b. After applying the agents 106a and 106b, the crystal blank 107 is placed on the extraction electrodes 105a and 105b by using the placement convex portion 103. At this time, the crystal piece 107 is placed so that the electrodes 107a and 107b of the crystal piece 107 are positioned on the extraction electrodes 105a and 105b, and the electrodes 107a and 107a of the crystal piece 107 are electrically conductive adhesives 106a and 106b. 107b and the extraction electrodes 105a and 105b are electrically connected, and the crystal blank 107 is mechanically held inside.
[0008]
However, in recent years, downsizing of the crystal blank 107 has been progressing along with downsizing of the crystal resonator. Therefore, when the extraction electrodes 105a and 105b are connected to the electrodes 107a and 107b of the crystal piece 107, the vibration of the crystal piece 107 caused by the spread of the conductive adhesives 106a and 106b on the crystal piece 107 side is clamped. It can no longer be ignored. That is, the loss of the vibration level (support loss) caused by the support of the crystal blank 107 cannot be ignored.
[0009]
Such an increase in the support loss of the crystal blank 107 has a disadvantage that the CI (crystal impedance) value of the crystal blank 107 is increased, and the performance of the crystal resonator is deteriorated.
[0010]
Therefore, the present invention has been made in view of the above points, and an object of the present invention is to provide a crystal resonator that can suppress the loss of supporting a crystal blank even when the size is reduced.
[0011]
[Means for Solving the Problems]
For the above purpose, the surface-mount type crystal resonator of the present invention includes a crystal blank having electrodes attached thereto, a container having at least an extraction electrode therein, and a convex formed on the electrode of the crystal blank. It has a connection member formed by bonding a conductive adhesive cured in a shape and a conductive adhesive applied on the extraction electrode to each other.
Further, the method of manufacturing a surface-mounted crystal resonator of the present invention is a method of manufacturing a surface-mounted crystal resonator in which a crystal piece having electrodes attached thereto is housed in a container having an extraction electrode therein. A step of curing the conductive adhesive on the electrode of the crystal blank in a convex shape, a step of applying a conductive adhesive on the extraction electrode, and a step of curing the conductive adhesive on the electrode of the crystal blank. Fixing the crystal blank in the container by adhering to the conductive adhesive with a conductive adhesive applied on the extraction electrode.
In other words, the present invention reduces the contact area by applying a conductive adhesive in a protruding shape on the side of the quartz piece that comes into contact with the extraction electrode and curing it, and then applying and bonding the conductive adhesive on the extraction electrode side. I made it. This makes it possible to reduce the support loss caused by the conductive adhesive, which is brought about by downsizing the crystal unit.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a surface mount type crystal unit as an embodiment of the present invention will be described.
FIG. 1 is a diagram showing an internal structure of a surface-mount type crystal unit (hereinafter, simply referred to as “crystal unit”). FIG. 1A is a top view, and FIG. Are shown respectively. Note that the cross-sectional view shown in FIG. 2B is a cross-sectional view of the crystal resonator taken along the dashed line shown in FIG.
[0013]
The crystal resonator shown in FIG. 1 is configured by housing a crystal piece 9 in an airtight container including a container body 1 and a lid 10.
The container main body 1 is formed of ceramic or the like, forms an intermediate ceramic layer on both sides of a base ceramic layer serving as a bottom plate 13, and forms an upper ceramic layer serving as a side wall on the periphery of the base ceramic layer in which the intermediate ceramic layers are stacked. It has a structure. That is, the container body 1 has a three-layer structure in which three ceramic layers of a base ceramic layer, an intermediate ceramic layer, and an upper ceramic layer are stacked.
In this case, the inner shape of the container body 1 is a box shape that is very shallow enough to accommodate the crystal blank 9.
[0014]
A metallized surface formed by metallizing (metallizing) ceramic is formed on the upper edge of the container body 1 as a bonding surface 4 for bonding the lid 10. The joining surface 4 may be formed by brazing a metal seal ring or the like as a joining surface material.
[0015]
On the outer bottom surface of the container body 1, for example, four electrode terminals 11, 11,... Are provided at the four corners, and two electrode terminals 11, 11, among these four electrode terminals 11, 11,. 11 are connected to the extraction electrodes 5a, 5b in the container body 1 by conductive lines 12, 12, respectively.
[0016]
On both sides of the inside of the container body 1, a protrusion 2 for an extraction electrode and a protrusion 3 for mounting are formed using the intermediate ceramic layer.
[0017]
The extraction electrode convex portion 2 is a portion that forms extraction electrodes 5a and 5b to which the electrodes 9a and 9b of the crystal blank 9 are connected. In this case, the extraction electrode projection 2 is divided into two regions by a gap G provided at the center thereof, and extraction electrodes 5a and 5b are formed in each region.
[0018]
As shown in FIG. 1B, the electrodes 9a and 9b of the crystal blank 9 are formed on the lower surface and the upper surface of the crystal blank 9 in the drawing. The electrode 9a on the lower surface has a pattern shape that faces the extraction electrode 5a but does not face the extraction electrode 5b. The electrode 9b on the upper surface is continuous with, for example, the side surface of the crystal blank 9 and is folded back toward the lower surface to form a portion facing the extraction electrode 5b. As a result, as described later, the electrode 9a and the extraction electrode 5a are connected, and the electrode 9b and the extraction electrode 5b are connected by the conductive adhesive.
[0019]
A conductive adhesive as a connecting member is applied to the electrodes 9a and 9b of the crystal blank 9 to form protrusions 7a and 7b (hereinafter simply referred to as "protrusions") which are cured in a protruding shape. The protrusions 7a, 7b and the extraction electrodes 5a, 5b are connected by conductive adhesives 6a, 6b as connecting members, and the extraction electrodes 5a, 5b and the electrodes 9a, 9b of the crystal piece 9 are electrically connected. At the same time, the crystal blank 9 is mechanically held therein.
[0020]
The contact area can be reduced by applying a conductive adhesive to the electrodes 9a and 9b of the crystal blank 9 in a projecting manner. The structure of the projections 7a and 7b will be described later.
[0021]
The connection member is, for example, a heat-shrinkable type, and uses a relatively soft silicone-based adhesive that can absorb an impact given to the crystal blank 9 to be connected. Of course, as long as the extraction electrodes 5a, 5b and the electrodes 9a, 9b can be electrically and mechanically connected, an adhesive other than silicon can be used as the connection member.
[0022]
The mounting projection 3 is provided to hold the other end of the crystal blank 9 not connected to the extraction electrodes 5a and 5b when connecting to the electrodes 9a and 9b of the crystal blank 9 and the extraction electrodes 5a and 5b. It functions as a receiving surface of the crystal blank 9.
[0023]
A method of fixing the crystal blank 9 in the container 1 using the protrusions 7a and the structure of the protrusions will be described with reference to FIG.
FIG. 2A is a diagram showing a state before the conductive adhesive is cured on the electrode 9a of the crystal blank 9 and the protruding protrusion 7a is connected to the conductive adhesive 6a applied to the extraction electrode 5a. (B) shows a state diagram after connection.
[0024]
First, a conductive adhesive is applied to a portion of the electrode 9a that faces the extraction electrode 5a, and the conductive adhesive is cured into a protruding shape. This is the projection 7a shown in FIG.
Subsequently, the conductive adhesive 6a is also applied to the extraction electrode 5a side.
After the projections 7a are formed in this manner, and the conductive adhesive 6a is applied to the extraction electrode 5a, the projections 7a are bonded to the conductive adhesive 6a by pressing them.
[0025]
FIG. 2B shows a state in which the cured projection 7a is connected to the conductive adhesive 6a on the extraction electrode 5a.
As described above, by curing the conductive adhesive of the electrode 9a of the crystal blank 9 first to form the projection 7a, the conductive adhesive spreads beyond the size of the projection 7a on the crystal blank 9 side. Therefore, the influence of the support loss on the crystal blank 9 can be reduced.
[0026]
The process of forming the projections and then bonding the same as described above is the same as the bonding between the electrode 9b side of the crystal piece 9 and the extraction electrode 5b. Therefore, the conductive bonding on the crystal piece 7 side by the projections 7b. The spread of the agent 6a is prevented.
The reduction of the support loss in this way is very suitable in view of the downsizing of the crystal blank 9 accompanying the downsizing of the crystal unit.
[0027]
Note that, in the above example, the protrusions formed by curing the conductive adhesive were formed on the electrode on the quartz piece side, but the protrusions formed by curing the conductive adhesive in the same manner were formed on the extraction electrode side, and the crystal was formed. A conductive adhesive may be applied and bonded to one of the electrodes. In this case, the same effect can be obtained by reducing the area of application to the electrode on the one side of the quartz crystal.
[0028]
【The invention's effect】
As described above, the surface-mount type crystal resonator of the present invention can prevent the crystal piece from being unnecessarily connected to the extraction electrode when the electrode of the crystal piece and the extraction electrode are connected to each other by the connecting member. The loss is reduced and the performance of the vibrator is prevented from deteriorating.
Therefore, a high-quality crystal resonator can be provided even when the crystal resonator is downsized in order to apply such a crystal resonator of the present invention to a downsized mobile communication device.
[Brief description of the drawings]
1A and 1B are a top view and a cross-sectional view illustrating an internal structure of a crystal unit.
FIG. 2 is a view schematically showing a state of adhesion between an electrode of a crystal piece and an extraction electrode shown in FIG.
FIG. 3 is a top view and a cross-sectional view for explaining the internal structure of a conventional crystal unit.
FIG. 4 is a diagram schematically showing a state of adhesion between an electrode of a conventional crystal blank and an extraction electrode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Container main body, 2 convex parts for extraction electrodes, 3 convex parts for mounting, 4 joint surfaces, 5a 5b extraction electrodes, 6a 6b conductive adhesive, 7a 7b protrusions, 9 crystal pieces, 9a 9b electrodes, 10 lids, 11 electrode terminal, 12 conductive line

Claims (2)

A crystal piece to which the electrodes are attached,
At least, a container configured to have an extraction electrode therein,
A conductive member hardened in a convex shape on the electrode of the crystal blank, and a conductive member applied on the extraction electrode, and a connection member bonded to each other, Surface mount type crystal unit. As a method of manufacturing a surface-mounted crystal resonator that houses a crystal piece with an electrode attached thereto, in a container configured with an extraction electrode therein,
A step of curing the conductive adhesive in a convex shape on the electrode of the quartz piece,
A step of applying a conductive adhesive on the extraction electrode,
Fixing the quartz piece in the container by bonding the conductive adhesive applied on the extraction electrode to the conductive adhesive that is cured in a convex shape on the electrode of the quartz piece. And a method for manufacturing a surface-mounted crystal resonator.

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