JP2001016069A - Surface mount type crystal unit - Google Patents

Abstract

(57) [Problem] To provide a surface mount type crystal unit that can be miniaturized and can be reduced in cost. SOLUTION: A vibrator main body 1 is made of a rectangular AT-cut quartz plate, and a thick portion 1 in which opposed short sides are thick.
1 and 12 and a thin portion 10 whose front and back surfaces are thinned in other regions. The case body 2 has a rectangular parallelepiped shape as a whole, is formed of quartz, and has a through hole 20 formed in a side surface. The vibrator main body 1 is inserted into the through hole 20 of the case main body 2, and the thick side surfaces 11 a and 12 a of the vibrator main body 1 and the side surfaces 21 a and 22 a of the through hole forming portion of the case main body 2 are positioned on substantially the same plane.

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.

[0002]

2. Description of the Related Art A conventional surface mount type crystal unit will be described with reference to FIG. The crystal unit 7 includes a ceramic package 70, a crystal plate 9 housed in the ceramic package 70, and a lid 8 hermetically sealing the crystal plate 9.
The ceramic package 70 is made of ceramics such as alumina, and has a rectangular parallelepiped shape with an open top, and a metal layer 71 made of tungsten, nickel, or the like is provided around the opening.
Are formed using a metallization technique and a plating technique. Support electrodes 72 and 73 for electrically and mechanically joining the quartz vibrating plate 9 are formed in the inside. These support electrodes 72 and 73 are connected to lead electrodes 74 via internal wiring using a known ceramic lamination technique. , 75, 76, 77 (partially not shown). Each lead-out electrode is formed near the outer periphery of the back surface 70a of the crystal unit.

The quartz vibrating plate 9 is a rectangular AT-cut quartz plate. Exciting electrodes 91 and 92 (92 not shown) are formed on the front and back surfaces, and conductive bonding materials (see FIG. (Not shown) to one end. The lid 8 has a configuration in which a substrate 80 is made of a metal plate or a ceramic plate, and a metal layer 81 made of nickel or the like is formed corresponding to the metal layer 71 on the package side. The ceramic package 70 and the lid 8 are welded together in an inert gas atmosphere or a reduced pressure atmosphere. As a joining method, known seam welding, laser welding, ultrasonic welding, or the like can be used.

[0004] Such a ceramic package has been widely used recently because a sealing method excellent in airtightness can be used. However, ceramic packages are relatively expensive due to the laminated structure, etc., and require a metal or ceramic lid for sealing, or the formation of a metal layer for hermetic sealing, etc. There was a problem that the number of points and the number of manufacturing steps increased.

[0005] Further, when the internal electrode wiring and the lead-out electrode are formed on the ceramic package by using the lamination technology, there is a problem that the structure cannot cope with ultra-miniaturization due to its configuration. For example, depending on the complexity of the configuration of the internal wiring, in consideration of good yield, a ceramic package having a length of 2.5 mm, a width of 2.0 mm, and a thickness of 0.7 mm is a limitation of miniaturization. Had become.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a surface mount type crystal unit which can be miniaturized and can be manufactured at low cost. It is an object.

[0007]

According to a first aspect of the present invention, there is provided a surface-mount type crystal unit comprising a rectangular crystal plate having a thick portion formed in at least one pair of opposed outer peripheral portions. A vibrator body having a thin portion at the center portion, an excitation electrode formed at the thin portion, and an extraction electrode drawn out from the excitation electrode to the thick portion, and a ceramic or glass or quartz crystal, A through-hole substantially corresponding to the outer size of the vibrator body, and a case body formed with lead-out electrodes at both ends of the through-hole. The main body is housed, and the extraction electrode and the extraction electrode are electrically and mechanically joined by a conductive joining material.

[0008] Further, as set forth in claim 2, the through hole formed in the case body may be formed by hollowing using a laser beam.

According to the above configuration, the components are mainly composed of the vibrator main body and the case main body, and the number of components can be reduced. In addition, since the extraction electrodes formed on the vibrator body are pulled out to the outside of the package, the internal wiring configuration by lamination used in ceramic packages and the electrical connection inside the package, which has been done in the past, become unnecessary. For example, it is possible to obtain an ultra-small quartz oscillator having a length of about 1.0 mm, a width of about 0.5 mm, and a thickness of about 0.3 mm.

According to the second aspect of the present invention, the formation of the through-hole is performed by a hollowing process using a three-dimensionally cut laser beam, so that the through-hole can be easily formed. Recently, for example, laser light with a wavelength suitable for cutting quartz has been developed,
A part of the case body is practically used, and the cut surface by the laser beam can be finished in an extremely good state, so that a case body with higher dimensional accuracy and quality can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are shown in FIGS.
This will be described with reference to FIG. FIG. 1 is an exploded perspective view showing the present embodiment, FIG. 2 is a perspective view showing a state in which the components shown in FIG. 1 are incorporated, FIG. 3 is a sectional view taken along line AA of FIG. 2, and FIG. It is a figure explaining the method of cutting out from a block using a laser beam.

The surface-mount type crystal resonator includes a resonator main body 1 and a case main body 2 having substantially equal longitudinal dimensions. The vibrator main body 1 is made of a rectangular AT-cut quartz plate, and includes thick portions 11 and 12 whose opposite short sides are thick, and a thin portion 10 whose front and back are thin in other regions. The formation of the thick portion and the thin portion is performed using, for example, a photoetching technique. Specifically, a quartz plate having a thickness equivalent to the thick portion is prepared, and the thick portion is masked with a resist film and etched to form a thin portion. Note that A
As is well known, the frequency of a T-cut quartz plate is determined by its thickness. Therefore, by monitoring the etching time, the frequency is roughly adjusted by etching. Then, the excitation electrodes 10a, 10a
b is formed. The excitation electrodes 10a and 10b are thick portions 1
1 and 12 and an extraction electrode 11 is provided around the thick portion.
b, 12b. The excitation electrode and the extraction electrode are formed, for example, in the order of chromium and gold in contact with a quartz plate by a technique such as a vacuum deposition method. Although not shown, after forming the excitation electrode, a metal material may be partially vapor-deposited on the excitation electrode portion, and the frequency may be adjusted by the additional mass effect.

The case body 2 has a rectangular parallelepiped shape as a whole.
The through hole 20 is formed on the side surface. The through-hole 20 is formed in the thick portion 11 of the vibrator main body 1,
12 is set to a shape and size that can be penetrated. The formation of the through holes can be relatively easily performed by using laser beam cutting by well-known NC (NUMERICAL CONTROL) control.

FIG. 4 is a perspective view showing an example in which a large number of case bodies are cut by a laser beam 41 from a relatively large crystal block B. The laser beam cutting machine 4 is operated according to a predetermined cutting program, and the through holes 20 are cut out from the crystal block B at predetermined intervals. After that, the portion to be cut indicated by the dotted line is cut and separated into the case main body 2. Note that, in both opening portions of the through hole 20, for example, film-like lead electrodes 21 and 22 made of gold are formed on a chromium base.

In order to assemble the crystal oscillator, the oscillator main body 1 is inserted into the through hole 20 of the case main body 2,
The thick side surfaces 11a and 12a of the first case and the side surfaces 21a and 22a of the through hole forming portion of the case main body 2 are positioned on substantially the same plane. In this state, although not shown, a low-melting metal bonding material such as solder or a conductive resin adhesive is applied to the boundary between the two side surfaces to seal between the case main body and the vibrator main body and to connect the lead electrode. 11b, 12b and the lead-out electrodes 21, 22 are electrically connected.

A second embodiment according to the present invention will be described with reference to FIG. FIG. 5 is an exploded perspective view. The same components as those in the first embodiment will be described using the same reference numerals, and a description thereof will be partially omitted.

The case body 2 has the same configuration as that of the first embodiment, and has a configuration in which a through hole 20 and lead-out electrodes 21 and 22 are formed. The vibrator main body 3 has a configuration in which a thick portion 31 is formed around the entire periphery of a rectangular quartz plate, and a thin portion 30 serving as an excitation region is formed in the center. Excitation electrodes 30a and the like (the back surface is not shown) are formed on the front and back of the thin portion 30, and the excitation electrodes 30a and the like are drawn out to the outside by extraction electrodes 31a and 31b formed on the short sides of the thick portion 31. It is. The vibrator main body 3 is inserted into the case main body as in the conventional case, and is electrically and mechanically connected by soldering or the like. According to the present embodiment, since the thick part is formed around the vibrator main body, the mechanical strength can be improved.

In the above embodiment, an example is described in which quartz is used for the case body, but a case made of glass or ceramics may be used. The vibrator body is not limited to the AT-cut quartz plate, but may be a two-legged or three-legged tuning-fork type quartz oscillator. Further, the present invention can be applied to an MCF (monolithic crystal filter).

[0019]

According to the present invention, the components are mainly composed of the vibrator main body and the case main body, and the number of components can be reduced. In addition, since an expensive ceramic package using a lamination technique is not required unlike the related art, a low-cost surface-mount type crystal unit can be obtained.

Further, since the extraction electrodes formed on the vibrator main body are drawn out to the outside of the package, the conventional electrical connection inside the package becomes unnecessary, and the crystal resonator can be miniaturized. it can.

According to the second aspect of the present invention, since the through hole is formed by cutting with a three-dimensionally cut laser beam, the through hole can be easily formed, and the surface mount type crystal resonator can be reduced in size and cost. Can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment.

FIG. 2 is a perspective view showing the first embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a diagram illustrating a method for cutting out a crystal block using a laser beam.

FIG. 5 is an exploded perspective view showing a second embodiment.

FIG. 6 is a perspective view showing a conventional example.

[Description of Signs] 1, 3 Oscillator main body 10, 30 Thin part 11, 12, 31 Thick part 2 Case main body

Claims (2)

[Claims] 1. A rectangular quartz plate having at least one pair of opposed outer peripheral portions having a thick portion and a central portion having a thin portion and an excitation electrode formed at the thin portion, A vibrator body having an extraction electrode from which an electrode is drawn out to the thick portion; and a through-hole substantially corresponding to the outer size of the vibrator body is formed in a central portion, the through-hole being formed of ceramics, glass, or quartz. A case body in which lead-out electrodes are formed at both end portions of the hole; a vibrator body is housed in a through-hole of the case body; A surface mounted crystal unit characterized by being bonded. 2. A surface-mount type crystal unit, wherein a through hole formed in a case body is formed by hollowing using a laser beam.