JPH0131802B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric vibrator that functions as a thickness-shear vibrator.

Conventionally, AT is an example of a thickness-shear piezoelectric vibrator.
In the cut crystal unit, a holding spring is fixed to two terminal pins of an airtight terminal by welding, etc., a crystal piece is supported between the two holding springs, and the cap is held in place without contacting the holding spring or the crystal piece. The base of the terminal and the cap were sealed together. This resulted in a large number of parts and a complex configuration. In addition, manufacturing and assembly are complicated, and the external shape is large. Furthermore, since the crystal piece is supported at two points, there is also the disadvantage that it is susceptible to impact.

The present invention eliminates the above-mentioned drawbacks, and aims to provide a thin-thickness sliding piezoelectric vibrator that has a simple structure, a small number of parts, is easy to manufacture and assemble, is resistant to impact, and has a small external shape. It is something.

Examples of the present invention will be described in detail below.

In FIG. 1, reference numeral 1 denotes an AT-cut crystal resonator as an example of a thickness-shear resonator, in which a crystal piece 2 that performs thickness-shear vibration is attached to adhesive layers 3 and 4 corresponding to its outer peripheral edge with spacers 5, Insulating flat substrates 7 and 8 are sealed by adhesive layers 3 and 4 with substrates 6 interposed therebetween.

As shown in the second figure, the crystal piece 2 has drive electrodes 2a and extraction electrodes 2b extending to the outer peripheral end formed on both main surfaces by vapor deposition. is formed in a convex shape, concentrating the vibration energy of thickness shear vibration in the center, and minimizing vibration displacement at the outer peripheral end.

If the adhesive layers 3 and 4 themselves are made thick so that the central portion of the convex main surface of the crystal piece 2 does not come into contact with the substrates 7 and 8, problems arise in terms of adhesive strength and airtightness.
For this reason, spacers 5 and 6 are interposed between the adhesive layers 3 and 4 to ensure the required adhesive strength and airtightness.

The spacers 5 and 6 are, as shown in FIGS. 3 and 4,
A ring-shaped portion 5a that can face the outer periphery of the crystal piece 2,
6a, and pull-out terminals 5b, 6b extending outward. The material for the spacers 5 and 6 is preferably a metal thin plate having a thermal expansion coefficient similar to that of the crystal blank 2, and in this example, an iron-nickel alloy containing 50% iron and 50% nickel is used.

For the substrates 7 and 8, an insulating material such as ceramic or glass, which has a coefficient of thermal expansion close to that of the crystal piece and has no air permeability, is suitable.

The adhesive layers 3 and 4 are made of an anisotropically conductive adhesive. This anisotropic conductive adhesive is a mixture of an insulating adhesive and silver powder, etc. at a concentration of about 20 to 40% by weight, and exhibits conductivity only in the thickness direction (pressing direction).
The horizontal direction indicates insulation. Drive electrode 2a
The lead electrode 2b and the ring-shaped portions 5a, 6a of the spacers 5, 6 are electrically connected to each other by the adhesive layers 3, 4, which are anisotropic conductive adhesives. Since the adhesive layers 3 and 4 are made of an anisotropic conductive adhesive, the crystal piece 2
Even if the adhesive layers 3 and 4 protrude and come into contact with each other at the outer peripheral edge, there will be no short circuit.

Space between crystal piece 2 and substrate 7 and crystal piece 2
The space between and the substrate 8 is airtight,
Vacuum or inert gas replacement. Note that the airtightness can be further improved by filling the outer peripheral portion of the crystal piece 2 with wax or the like so as to be in contact with the substrates 7 and 8.

As described above, according to the present invention, when sandwiching and sealing a piezoelectric element between a pair of substrates, this sandwiching and sealing is performed using an adhesive layer made of an anisotropic conductive adhesive, and the adhesive layer Since a spacer with a pull-out terminal for external connection is interposed between the spacer and the piezoelectric element, conduction between the spacer and the piezoelectric element can be established at the same time as sealing, and even if the adhesive spills out during the sealing process, there will be no short circuit. There is no. Therefore, manufacturing and assembly becomes very easy. Further, since the number of parts is small and the configuration is simple, it can be made smaller. moreover,
It is possible to provide a thickness-shear piezoelectric vibrator with excellent impact resistance and airtightness.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a front view of a crystal piece, and FIGS. 3 and 4 are front views of a spacer. DESCRIPTION OF SYMBOLS 1... Crystal resonator, 2... Crystal piece, 2a... Drive electrode, 2b... Extraction electrode, 3, 4... Adhesive layer, 5, 6... Spacer, 5a, 6a... Ring-shaped part, 5b , 6b... Output terminal, 7, 8... Board.

Claims (1)

[Scope of Claims] 1. A piezoelectric element that performs thickness sliding, in which a drive electrode and an extraction electrode extending from the drive electrode to an outer peripheral end are formed on both main surfaces; A pair of flat insulating substrates located opposite both main surfaces, and an anisotropically conductive adhesive sealing between the outer peripheries of both main surfaces of the piezoelectric element and both insulating substrates. The formed adhesive layer and the piezoelectric element are embedded in the adhesive layer in order to keep both main surfaces of the piezoelectric element in a non-contact state with both the insulating substrates, and the piezoelectric element is embedded in the adhesive layer through the anisotropic conductive adhesive. A pair of metal spacers comprising a ring-shaped part that is electrically connected to the extraction electrode, and an extraction terminal for external connection that is integrally formed and extends outward from the ring-shaped part. A thickness-slip piezoelectric vibrator characterized by: