JP2002111427A - Surface mounting quartz vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mounting vibrator improved well in impact resistance by preventing breakage of a quartz fraction. SOLUTION: In this surface mounting quartz vibrator opposing a main plane of a quartz fraction to a base, connecting electrically and mechanically one edge of the quartz fraction to the base by a conductive bonding agent and closing and sealing the quartz fraction by covering a cover on the base, a protruding portion is arranged in a inner surface of the cover and the protruding portion is positioned in the other edge of the quartz fraction. Moreover, the conductive bonding agent is coated on the upper and lower surfaces covering the one edge of the quartz fraction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mounted crystal resonator (hereinafter referred to as a "surface mounted resonator") as an industrial technical field. The present invention relates to a surface mount resonator.

[0002]

2. Description of the Related Art Surface mount resonators are widely used in various electronic devices including communication devices, particularly portable devices, as frequency and time reference sources. One of such devices is a surface mount resonator in which one end of a crystal blank is electrically and mechanically connected by a conductive adhesive.

(Example of Prior Art) FIGS. 3 to 5 are views for explaining a conventional example. 3 is a cross-sectional view of the surface mount resonator, FIG. 4 is a plan view of a crystal blank, and FIG. 5 is a plan view of a concave container. The surface mount resonator is configured such that a crystal blank 2 is housed in a concave container 1 as a base made of a laminated ceramic, covered with a cover 3, and hermetically sealed. The concave container 1 has a pair of crystal terminals 4 on the bottom surface, and surface mounting terminals (referred to as mounting terminals) 5 extend from the lamination surface to both ends of the outer surface. The crystal blank 2 has excitation electrodes 6 on both main surfaces, and extraction electrodes 7 extend on both sides of one end.

Then, both ends of the crystal piece 2 are fixed to the crystal terminal 4 on the bottom surface of the concave portion with a conductive adhesive 8, and are electrically and mechanically connected (held). The conductive adhesive 8 is applied to only the lower surface of one end of the crystal blank 2 (not shown), or is applied to the upper and lower surfaces so as to cover the one end as shown. A metal ring 9 is soldered to the opening surface of the concave container 1, and the cover 3 is joined by seam welding.

[0005]

[Problems to be Solved by the Invention]
However, in the surface mount resonator having the above configuration, only one end of the crystal blank 2 is held, so that when there is an impact or the like, the other end of the crystal blank 2 jumps up and bends (warps). If the amount of bending exceeds the limit value of the crystal blank 2, there is a problem that the crystal is broken and the impact resistance is deteriorated. Conventionally, it is considered that the other end of the crystal blank 2 collides with the cover 3 due to an impact and is broken, so that a certain distance or more is provided between the two.

Therefore, it is conceivable to make the gap between the crystal blank 2 and the cover 3 small. However, if the product is standardized as a mass-produced product, the design cannot be easily changed. In addition, since the gap between the crystal blank 2 and the cover 3 changes depending on the thickness of the conductive adhesive 8, it has been difficult to set the height to allow for this. In particular, when the conductive adhesive 8 is also applied to the upper surface of the crystal blank 2, the conductive adhesive 8 may come into contact with the cover 3 and cause an electrical short circuit.

In the above example, the cover 3 is joined to the opening surface of the concave container 1 by seam welding. Normally, one metal plate is punched by press working to obtain many covers 3 at a time. However, burrs are generated on the other main surface opposite to the one main surface on which the cutting edge of the press machine contacts. For this reason,
For example, when seam welding is performed with the opposite surface having burrs on the opening surface side of the concave container 1, the bonding surfaces are not sufficiently adhered to each other, so that the bonding strength is reduced or airtight leakage occurs.

For this reason, conventionally, for example, after a large number of covers are subjected to barrel polishing to remove burrs, the direction of the joint surface is released and seam welding is performed. However, in this case, there is a problem that productivity is hindered because a barrel polishing step is required.

In such a surface-mounted vibrator holding one end, the distance of the wiring pattern from the excitation electrodes 6 on both main surfaces to the mounting terminals 5 is different. Therefore, when the mounting terminal 5 of the surface mount resonator is inverted and incorporated in the oscillation circuit, the oscillation frequency may change due to the asymmetry of the capacitance on the circuit side. For this reason, usually, a notch is provided in, for example, one of the mounting terminals 5 to recognize the directionality, and the pair of mounting electrodes of the surface-mounted vibrator are incorporated in the oscillation circuit with the specified directions.

However, even in this case, there is a problem that after mounting the surface-mounted resonator on the circuit board on which the oscillation circuit is formed, the notch is hidden and cannot be recognized, and the directionality after mounting cannot be confirmed.

(Object of the Invention) It is an object of the present invention to provide a surface mount resonator having improved shock resistance by preventing breakage of a crystal blank.

[0012]

According to the present invention, a basic solution is to provide a projection 10 on the inner surface of a cover and position the projection 10 on the other end of the crystal blank.

[0013]

According to the present invention, since the protrusion 10 is provided on the inner surface of the cover and located at the other end of the crystal blank, the bending of the other end of the crystal blank due to the jump is suppressed. Hereinafter, an embodiment of the present invention will be described.

[0014]

FIG. 1 is a sectional view of a surface-mount vibrator for explaining an embodiment of the present invention. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted. As described above, the surface mount resonator holds one end of the crystal blank 2 in a concave container 1 having a pair of crystal terminals 4 and mounting terminals 5 and covers the crystal blank 2 by seam welding.
Is sealed.

In this embodiment, projections 10 are provided on the inner surface of the cover 3 on both sides at one end. The protruding portion 10 is pushed in from the other main surface toward one main surface, and is formed integrally with the cutting at the time of press working. That is, the protruding portion 10 protrudes on one main surface opposite to the other main surface on which burrs occur. Then, one end of the cover 3 on which the protruding portion 10 is formed is positioned on the other end side of the crystal blank 2, and one main surface side is joined to the concave container 1.

With such a configuration, even if the other end of the crystal blank 2 jumps up at the time of impact, the projecting portion 10 limits the jumping distance. Therefore, without newly designing the concave container 1, the bending of the crystal blank 2 can be suppressed to a limit and breakage can be prevented. In addition, even if the height of the concave container 1 is different, by changing the length of the protruding portion 10,
Can be controlled, and various concave containers 1 can be handled.

Further, in this example, the front and back of the cover 3 can be recognized by the protrusion 10. Then, since one main surface side of the protruding portion 10 having no protruding burrs is seam-welded, joining strength is ensured. Therefore, the step of removing burrs by barrel polishing or the like becomes unnecessary, so that productivity can be improved.

Further, since one end of the crystal blank 2 can be recognized by the position of the protruding portion 10 provided on the cover 3, even after mounting on the circuit board on which the oscillation circuit is formed,
The direction of the crystal unit can be checked. Furthermore, cover 3
The front and back can be recognized.

[0019]

[Others] In the above embodiment, the protruding portions 10 of the cover 3 are formed on both sides at one end in a dotted manner. In addition, the protruding portion 10 is formed by pressing from the outer surface, but may be formed by applying an adhesive, for example (not shown). However, the former is advantageous because it can be formed integrally.

Although both ends of the crystal piece 2 are held on the bottom surface of the concave container 1, a step may be provided on the side wall of the concave container 1 to hold one end of the crystal piece 2. In this case, a crystal oscillator may be configured by disposing electronic elements such as the IC chip 11 on the lower surface of the crystal blank 2.

Although the cover 3 is formed by seam welding as a metal, the present invention is not limited to this, and may be beam welding or resin sealing or glass sealing using the cover 3 as an insulating material. And although the base which holds the crystal blank 2 was the concave container 1,
The same applies to the case where the base is flat and the cover 3 is concave.

[0022]

According to the present invention, since the projection is provided on the inner surface of the cover and located on the other end side of the crystal blank, damage to the crystal blank is particularly prevented, and the surface mounting with improved impact resistance is provided. A vibrator can be provided.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a surface-mount vibrator for explaining another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a surface-mount vibrator for explaining a conventional example.

FIG. 4 is a plan view of a crystal piece illustrating a conventional example.

FIG. 5 is a plan view of a concave container for explaining a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Concave container, 2 crystal pieces, 3 covers, 4 crystal terminals, 5 mounting terminals, 6 excitation electrodes, 7 extraction electrodes, 8 conductive adhesives, 9 metal rings, 10 protrusions, 11 I
C chip.

Claims (3)

[Claims] 1. A main body of a crystal blank faces a base, one end of the crystal blank is electrically and mechanically connected to the base by a conductive adhesive, and the base is covered with a cover. In a crystal resonator for surface mounting in which a piece is hermetically sealed, a projection is provided on an inner surface of the cover, and the projection is located on the other end side of the crystal piece. Vibrator. 2. The crystal unit according to claim 1, wherein said conductive adhesive is applied to upper and lower surfaces to cover one end of said crystal blank. 3. The crystal unit according to claim 1, wherein the base is a concave container, the cover is metal, and the cover is joined to the concave container by seam welding.