JPH0334713A - Surface mount type piezoelectric resonator - Google Patents

Abstract

PURPOSE:To obtain excellent vibration and shock resistance characteristic by providing at least two support electrodes to one side face of a bottom plate, placing a lead terminal of the electrode of a piezoelectric chip leading an exciting electrode to one terminal, placing a retainer to the leadout terminal and adhering it to a support base with an adhesives. CONSTITUTION:An insulation member made of a ceramic or glass or the like is formed flat or a shape whose cross section is of recessed shape as a bottom plate 12 and one side face of a seal ring 11 is fixed to one end face of the bottom plate. Then a couple of support electrodes 13 are formed to the end of the bottom plate 12 by the metallizing treatment or the like and a support base 14 having a height of nearly 50mum almost equal to the height of the support electrodes 13 is formed to both sides. Then the piezoelectric chip 15 such as a quartz crystal is cut off to a prescribed angle and ground to form an exciting electrode on the plate and a lead is formed to one end. Then a retainer 16 is placed onto the electrode lead terminal of the piezoelectric chip 15 and the retainer 16 is adhered to the bottom plate 12 by an adhesives 17. As a result, the excellent vibration and shock resistance characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a surface-mounted piezoelectric vibrator, and particularly to an improvement in a holding structure for a piezoelectric piece.

(Technical Background of the Invention and Problems thereof) Recently, surface-mounted components have been widely used in various electronic components for the purpose of automating assembly processes and increasing packaging density.

For this reason, surface-mounted types of pressure sensors such as crystal oscillators are also manufactured.

FIG. 3 is a perspective view showing one side of a conventional surface-mounted crystal resonator, and FIG. 4 is a perspective view of the bottom plate.

In the figure, l is a metal seal ring formed into a substantially rectangular shape. A bottom plate 2 made of ceramic, glass, or the like is airtightly attached to one side of the seal ring 1 using adhesive, low-melting glass, brazing material, or the like to form a container. Note that in the case of joining using brazing material, for example, a metal film is baked onto a predetermined portion of the bottom plate 2, and the seal ring 1 is attached thereto. Furthermore, an electrode 2a for mounting on a printed circuit board or the like is formed on the outer surface of the bottom plate 2.

In this container, a crystal piece 3 etc., which has been adjusted to a predetermined resonant frequency by forming electrodes on the front and back surfaces, is housed.

In this case, there is two-end holding in which electrodes are led out to both ends of the crystal piece and held there, and one-end holding in which electrodes are led out and held at one end of the crystal piece.

Holding both ends and holding one end each have advantages and disadvantages, but if the expansion coefficients of the bottom plate 2 and the piezoelectric piece 3 are different, holding one end is preferable in that the stress caused by the difference in expansion coefficient due to temperature change does not act on the piezoelectric piece 3. is excellent.

Therefore, an electrode is led out from one end of the crystal piece 3, and a holding electrode 4 is formed at a predetermined position on the bottom plate 2 corresponding to this lead-out end, and the end of the crystal piece 3 is placed here and conductive adhesive is applied. They are fixed using adhesives, etc., and electrical connections are made.

A lid body 5 made of metal, for example, is placed on the other side of the seal ring 1, and the lid body 5 is airtightly sealed by seam welding.

However, in this type of device, the bonding surface (n) between the bottom plate and the piezoelectric piece becomes small, and stress is concentrated at the bonding site because the piezoelectric piece is held at one end, which causes problems in vibration resistance and FI4 south shock performance. was there.

(Object of the Invention) The present invention has been made in view of the above circumstances, and provides a surface-mounted piezoelectric S actuator that can obtain good vibration resistance and impact resistance in a structure that holds one end of a piezoelectric piece. The purpose is to

(Summary of the Invention) The present invention forms a container by airtightly attaching a bottom plate made of an insulating material to one side of a metal seal ring, and at least two holding electrodes are provided on one side of the bottom plate. Then, place the lead-out end of the electrode of the piezoelectric piece from which the excitation electrode has been led out on one end, place a presser plate on this lead-out end, fix it to the holding base with adhesive, and attach the other side of the seal ring to the lid body. It is characterized by being hermetically sealed.

(Embodiment) An embodiment of the present invention will be described below with reference to the perspective view of the bottom plate shown in FIG. 1 and the cutaway front view shown in FIG. explain.

In the figure, reference numeral 11 denotes a seal ring formed into a substantially rectangular shape and made of Kovar, 4270I, nickel silver, or the like. A bottom plate 12 made of an insulating material is airtightly attached to one side of the seal ring 11. The bottom plate 12 is formed of an insulating material such as ceramic or glass into a flat plate shape or a concave cross section, and is fixed to one side of the seal ring 11 on the negative side thereof.

A pair of holding electrodes 13 are formed at the ends of the bottom plate 12 by metallization or the like, and holding stands 14 having a height of about 50 μm, which is approximately the same as the holding electrodes 13, are formed on both sides of the holding electrodes 13. Note that the holding base 14 does not need to be provided, and may be made of the same metal film as the holding electrode, so for example, the pair of holding electrodes 13 and the holding base 14 may be simultaneously formed in predetermined positions by metallization treatment or the like. .

Also, on the outer surface of the bottom plate 12, there is a connection electrode electrically connected to the holding electrode 13 for mounting on a printed circuit board or the like. 2a is formed.

Then, a piezoelectric piece 15, k, for example, a quartz crystal, is cut at a predetermined angle and polished, an excitation TFi electrode is formed on the plate surface, and an excitation TFi electrode is led out at one end, and the lead-out end of the electrode of the crystal piece is adjusted to a predetermined resonance frequency. is placed on the holding electrode 13, fixed with a conductive adhesive, and electrically connected.

Furthermore, a presser plate 16 is placed on the lead-out end of the piezoelectric piece 15, and the presser plate 16 is fixed to the bottom plate 12 with an adhesive 17.

In this case, the bonding surfaces of the piezoelectric piece 15 and the presser plate 16 may or may not be bonded.

Then, a lid 18 made of metal, for example, is placed on the other side of the seal ring 11 and hermetically sealed by seam welding. Note that the container may be sealed by, for example, welding a glass lid using low-melting glass or the like.

With such a configuration, since the piezoelectric piece 15 is held at one end, stress due to a difference in coefficient of thermal expansion from the bottom plate 12 is not applied, and good aging characteristics can be obtained.

A holding plate 16 is placed on the electrode lead-out end of the piezoelectric piece 15 from L, and this holding plate 1n is fixed to the bottom plate 12 with an adhesive 17 to obtain good copper vibration and white 1 impact resistance. be able to.

Note that the present invention is not limited to the above embodiments,
For example, in the above embodiment, the explanation was given using crystal vibration -f as an example, but it goes without saying that it can also be applied to a resonator made of a piezoelectric material such as tantalum oxide.

(Effects of the Invention) As described in detail below, according to the present invention, it is possible to obtain good vibration resistance and impact resistance by holding one end of the piezoelectric body, and the structure is simple, suitable for miniaturization, and has excellent aging characteristics. It is also possible to provide a good surface-mount piezoelectric vibrator.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a bottom plate of an embodiment of the present invention, Fig. 2 is a cutaway front view of a vibrator of an embodiment of the present invention, and Fig. 3 is one side of a conventional surface-mount type vibrator. FIG. 4 is a perspective view showing the bottom plate of the conventional vibrator. 11 ・ 12 ・ l 3 ・ l 4 ・ l 5 ・ l 6 ・ l 7 ・ 18 ・ Seal ring, bottom plate, holding electrode, holding stand, piezoelectric piece, holding plate, adhesive, lid No. 1 Figure 4 3 3 4 Figure 2 1st day

Claims (1)

[Claims] A seal ring made of metal, a bottom plate made of an insulating material that is airtightly attached to one side of the seal ring to form a container, and at least one pair of retainers provided on one side of the bottom plate. an electrode, a piezoelectric piece in which an excitation electrode formed on a plate surface is led out at one end, and this lead-out end is fixed to the holding electrode with a conductive adhesive and electrically connected; and the lead-out end of this piezoelectric piece. A surface mount type, characterized by comprising: a presser plate placed on the base plate, an adhesive that fixes the presser plate to the bottom plate, and a lid that airtightly seals the other side of the seal ring. Piezoelectric vibrator.