JPH1131941A - Surface mount type crystal vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mount type crystal vibrator which can obtain excellent vibration characteristics and which are small-sized, low in cost, and suited for mass-production. SOLUTION: A crystal piece 3 formed in an outwardly hexagonal shape is put in a container 1 which is made of an insulating material and has an opening on its top surface. In such an arrangement, exciting electrodes 4 are formed on the top and reverse surfaces of the crystal piece opposite to each other and led out to corners; and the container is provided with step parts 5 in a shape conforming to the corners of the crystal piece, and a holding electrode 6 which conducts to a mount electrode 2 formed on the outside bottom surface is formed at the step parts. This holding electrode 6 supports the crystal piece 3, the lead-out end of the exciting electrode 4 is fixed to the holding electrode and electrically connected with a conductive adhesive 7, and the top surface of the container 1 is sealed hermetically with a lid body 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type crystal unit using a hexagonal crystal piece.

[0002]

2. Description of the Related Art In recent years, there has been a tendency that surface-mounted electronic components are frequently used in order to reduce the size and weight of electronic devices and to automate the assembly process. For this reason, it is desired that the crystal unit is small in size and surface-mounted. However, there are two problems to be solved in order to realize a small and surface-mount type crystal unit.

[0003] The first problem is that since the quartz oscillator utilizes the piezoelectric oscillation of quartz, it is necessary to hold the quartz oscillator in a space and place it in a chemically and physically stable atmosphere. Therefore, it is necessary to hold the crystal blank in a container having a certain capacity and to hermetically seal the container. However, it is difficult to accurately position and disassemble a small quartz piece in a small-sized container and to securely seal the container.

[0004] The second problem is that in order to realize a small-sized crystal resonator, it is necessary to use a crystal piece having a remarkably small size as compared with a conventional crystal piece. However, a crystal piece having a small shape makes it difficult to obtain good vibration characteristics, and this tends to cause problems such as an increase in crystal impedance, making it difficult to vibrate, and the occurrence of auxiliary vibration.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface mount type crystal resonator which is small in size and can obtain good vibration characteristics. Is what you do.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a container made of an insulating material having an opening on the upper surface and containing a crystal piece having a hexagonal outer shape. An excitation electrode formed and led out to the corner in the opposite direction, a step formed into the container in a shape corresponding to the corner of the crystal blank, a mounting electrode formed on the outer bottom surface of the container, and A holding electrode connected to the excitation electrode while supporting the corner of the quartz piece formed on the step portion and conducting with the electrode; and a conductive adhesive for bonding the corner of the quartz piece to the holding electrode to conduct the corner. And a lid for hermetically sealing the upper surface of the container.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the plan view of the inside of the container shown in FIG. 1, the perspective view of the container shown in FIG. 2, and the sectional side view shown in FIG.

A substantially cubic container 1 having an opening on the upper surface is formed from an insulating material such as ceramic. A mounting electrode 2 for mounting on a conductive pattern on a printed circuit board is provided on the outer bottom surface of the container 1. Then, the crystal blank 3 whose outer shape is formed into a hexagon is stored in the container 1. This crystal blank 3
Is, for example, an AT-cut crystal piece cut from an artificial quartz crystal.

The crystal blank 3 is formed into a hexagon having a corner of the direction of ± 45 ° of the Z ′ axis, and the excitation electrode 4 is formed on the front and back plate surfaces by vacuum evaporation or the like. Then, the respective excitation electrodes 4 are led out to the corners of the plate surface of the crystal blank 3 in opposite directions. A step 5 having a shape corresponding to the corner of the crystal blank 3 is formed in the container 1, and a holding electrode 6 electrically connected to the mounting electrode 2 is formed on the step 5.

The corners of the crystal blank 3 are supported by the step 5, and a conductive adhesive 7 is applied to the corners to mechanically hold the same. For electrical continuity. Then, the lid 8 is placed in the opening on the upper surface of the container 1.
Is mounted, and the opening is hermetically sealed by bonding with, for example, molten glass.

In this way, the crystal blank 3 is held at the step 5 corresponding to the shape of the corner, and the conductive adhesive 7 is applied thereto, so that the positioning can be easily and accurately performed. It can be performed. Since the lid 8 is placed on the opening on the upper surface and, for example, is adhered, a design that can obtain a relatively large adhesive area on the upper surface of the container 1 can be performed. It is possible to perform sealing capable of obtaining airtightness.

[0012] Particularly, in the case of an AT-cut crystal blank,
If the size is reduced to, for example, the Z'-axis direction as the longitudinal direction and the dimension is 5 mm or less, the center of the sub-vibration is often located near the end in the longitudinal direction. Therefore, when the whole is formed into a hexagon with the direction of the Z ′ axis ± 45 ° as a corner as in the above-described crystal blank 3, the center portion of the sub-vibration can be cut off, thereby suppressing the sub-vibration. And good vibration characteristics can be obtained.

The present invention is not limited to the above-described embodiment of the present invention. For example, the container may be made of inexpensive glass instead of ceramic, and the sealing method may be used. It goes without saying that the lid may be sealed by seam welding or the like instead of bonding the lid.

[0014]

The present invention is embodied in the form described above and has the following effects.

It is possible to easily manufacture a crystal resonator having an extremely small shape, to provide a surface-mounted crystal resonator having good vibration characteristics and low cost.

[Brief description of the drawings]

FIG. 1 is a plan view of the inside of a container showing an example of a quartz oscillator of the present invention.

FIG. 2 is a perspective view showing a container of the crystal unit shown in FIG. 1;

FIG. 3 is a side sectional view of the crystal unit shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Mounting electrode 3 Quartz piece 4 Excitation electrode 5 Step part 6 Holding electrode 7 Conductive adhesive 8 Lid

Claims (3)

[Claims] 1. A container made of an insulating material having an opening on an upper surface and containing a crystal piece having a hexagonal outer shape, wherein the crystal piece is formed so as to face the front and back plate surfaces of the crystal piece, and corners are formed in opposite directions to each other. An excitation electrode led out, a step formed into the container in a shape corresponding to the corner of the crystal blank, a mounting electrode formed on the outer bottom surface of the container, and the step connected to the mounting electrode. A holding electrode connected to the excitation electrode while supporting the corner of the quartz piece; a conductive adhesive for bonding the corner of the quartz piece to the holding electrode to conduct electricity; and A surface mount type crystal unit, comprising: a lid body for sealing; 2. The surface-mount type crystal unit according to claim 1, wherein the container is made of ceramic. 3. A surface-mount type crystal resonator according to claim 1, wherein the crystal blank is AT-cut, and the corner is located in a direction of ± 45 ° of the crystal's Z ′ axis. .