JPH0131801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric vibrator that performs thickness shear vibration.

Conventionally, AT is an example of a thickness-shear piezoelectric vibrator.
Kattu's crystal resonators are made by fixing a holding spring to the two terminal pins of an airtight terminal by welding or other means, supporting the crystal piece between the two holding springs, and attaching the cap without contacting the holding spring or the crystal piece. The base of the airtight terminal and the cap were sealed. 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 provides a shear piezoelectric vibrator with a simple structure, a small number of parts, easy manufacture and assembly, strong impact resistance, and a small external shape.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In Figs. 1 to 3, reference numeral 1 denotes a thickness-shear crystal resonator, which includes a crystal piece 2 that performs thickness-shear vibration, and a circular pattern provided on both sides of the crystal piece corresponding to the outer peripheral edge of the crystal piece. It is composed of two flat substrates 5, 6 to which the center portions of both main surfaces 2a, 2b of a crystal piece are fixed in a non-contact state by adhesive layers 3, 4. The crystal piece 2 has a plano-convex shape, and concentrates the vibration energy of thickness-shear vibration in the center.
The vibration displacement at the outer peripheral end is set to be extremely small. Drive electrodes 7 and 8 are formed on both main surfaces 2a and 2b of the crystal blank 2 by vacuum deposition or the like. Denoted at 7a and 8a are lead-out electrodes of the drive electrodes 7 and 8, which are formed to extend in opposite directions to the outer peripheral end of the crystal piece 2, respectively. The substrates 5 and 6 are made of ceramic or the like having a coefficient of thermal expansion similar to that of the crystal piece 2, and in this embodiment, the conductor patterns 9 and 10 are formed by printing or the like and have the same shape. The conductor patterns 9, 10 are composed of ring-shaped parts 9a, 10a corresponding to the outer periphery of the crystal blank 2, and drawn-out parts 9b, 10b that are continuous with the ring-shaped parts 9a, 10a and extended to the ends of the substrate. The adhesive layers 3 and 4 are conductive patterns 9,
An anisotropically conductive adhesive is formed by printing in correspondence to the ring-shaped portions 9a and 10a of 10. This anisotropic conductive adhesive is an insulating adhesive mixed with 20 to 40% by weight of conductive particles such as silver powder, and is conductive in the thickness direction (pressing direction) and insulating in the width direction. It is. Also, in this example,
Spacer particles of about 200μm are mixed in,
The main surfaces 2a and 2 of the crystal piece 2 are caused by these spacer particles.
A gap is set between the crystal blank 2 and the substrates 5 and 6 to maintain non-contact between the crystal piece 2 and the substrates 5 and 6. The drive electrode 8 is connected to the ring-shaped part 9a and the lead-out part 9b of the conductive pattern 9 via the adhesive layer 4 from the lead-out electrode 8a. Further, the drive electrode 7 is connected to the ring-shaped portion 1 of the conductor pattern 10 via the adhesive layer 4 from the extraction electrode 7a.
0a, and is connected to the drawer section 10b. Since an anisotropic conductive adhesive is used, even if the adhesive layer 3 and the adhesive layer 4 protrude and come into contact with each other, they are kept in an insulated state and are not electrically connected, and the lead electrodes 7a,
8a and ring-shaped portions 9a of conductor patterns 9 and 10,
10a can be electrically connected. The space between the crystal piece 2 and the substrates 5, 6 surrounded by the adhesive layers 3, 4 is airtight and replaced with a vacuum or an inert gas.

The assembly of the crystal resonator 1 begins with the ring-shaped portions 9 of the conductive patterns 9 and 10 formed on the substrates 5 and 6.
A conductive adhesive is printed on a and 10a to form circular adhesive layers 3 and 4. Then, the outer periphery of the crystal piece 2 is placed on the adhesive layer 4 in a nitrogen atmosphere, for example, so that the outer periphery of the crystal piece 2 corresponds to the adhesive layer 4. Furthermore, the substrate 5 is placed on the crystal piece 2. At this time as well, the outer periphery of the crystal piece 2 and the adhesive layer 3 are placed in correspondence with each other. A predetermined gap is provided between the crystal piece 2 and the substrates 5, 6 by the adhesive layers 3, 4, and the center portions of both main surfaces 2a, 2b of the crystal piece 2 are in a non-contact state with the substrates 5, 6. By heating after this, the adhesive layers 3 and 4 can be cured more quickly. The lead-out portion 9b of the conductor pattern 9 is connected to the lead-out electrode 8a of the drive electrode 8 via the adhesive layer 4, and the lead-out portion 10b
is the lead electrode 7a of the drive electrode 7 via the adhesive layer 3.
connected to.

As described above, the crystal resonator 1 has the following advantages: it has a small number of parts, is simple in structure, easy to assemble, can be miniaturized, and is resistant to impact.

It is also possible to fill the space between the substrates 5 and 6 on the outer periphery of the crystal piece 2 with wax to improve the airtightness. Further, a wiring pattern may be formed on at least one of the substrates, and electrical components or the like may be attached.

Next, another embodiment of the present invention will be described with reference to FIGS. 4 to 8. Reference numeral 11 designates a thickness-shear crystal resonator, which includes a crystal piece 12 that performs thickness-shear vibration, and circumferential adhesive layers 13 and 14 on both sides of the crystal piece, which correspond to the outer peripheral edges of the crystal piece. It is composed of two substrates 15 and 16 whose central portions of main surfaces 12a and 12b are fixed in a non-contact state. The crystal blank 12 has a plano-convex shape as in the previous embodiment, and drive electrodes 17, 18 and extraction electrodes 17a, 18a are provided on both main surfaces. Substrate 15,1
6 also uses a non-permeable substrate such as ceramic as in the previous embodiment, and the board 16 has a lead pattern 19a and a terminal pattern 19b, and the board 15 has a lead pattern 20 formed by printing conductive paste or the like. There is. and adhesive layer 1
3 and 14 are drawer patterns 20 and 19a, respectively.
intersects with The adhesive layers 13 and 14 are formed of an anisotropically conductive adhesive as in the previous embodiment. The lead electrode 17a of the drive electrode 17 is connected to the lead pattern 20 of the substrate 15, and the lead electrode 18a of the drive electrode 18 is connected to the lead pattern 1 of the board 16.
Connected to 9a. 21 is a conductive material such as solder or conductive adhesive;
0 and the terminal pattern 19b of the board 16.

The assembly of the crystal resonator 11 is almost the same as in the previous embodiment, and finally the lead pattern 20 of the substrate 15 and the terminal pattern 19b of the substrate 16 are connected with a conductive material 21 such as solder. Accordingly, when driving the crystal resonator 11, it is sufficient to connect a power source between the lead pattern 19a and the terminal pattern 19b of one of the substrates 16. Further, integrated circuit elements, wiring patterns, etc. constituting the oscillation circuit can be easily provided on the substrate 16.

In the above two embodiments, a plano-convex crystal piece is used as the piezoelectric element, but it may be biconvex, beveled, flat, etc., and other piezoelectric materials may also be used.

As described above, according to the present invention, electrical conduction of the piezoelectric element to the conductor pattern of the substrate can be measured at the same time as the piezoelectric element is sandwiched and sealed between a pair of substrates, and furthermore, this sandwiching and sealing is anisotropic. Since a conductive adhesive is used, even if the adhesive protrudes during the sealing operation, there will be no short circuit, and therefore the piezoelectric element can be sealed very easily. Furthermore, it is possible to provide a thickness-shear piezoelectric vibrator that has an extremely small number of parts, is simple in structure, is easy to manufacture and assemble, and is small, thin, and strong against impact.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a front view with the upper substrate omitted, Fig. 3 is a front view of the lower substrate, and Fig. 4 is a front view of another embodiment. 5 is a sectional view taken along the line of FIG. 4, FIG. 6 is a front view of the lower substrate, FIG. 7 is a front view of the crystal piece, and FIG. 8 is a front view of the upper substrate. 1, 11... Crystal resonator, 2, 12... Crystal piece, 3, 4, 13, 14... Adhesive layer, 5, 6, 1
5, 16... Substrate, 7, 8, 17, 18... Drive electrode, 7a, 8a, 17a, 18a... Leading electrode, 9, 10... Conductor pattern.

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; Located opposite both main surfaces,
a pair of flat insulating substrates having a conductor pattern for external connection facing the extraction electrode formed on a surface facing the piezoelectric element; an adhesive layer formed of an anisotropic conductive adhesive that seals between the piezoelectric element and the insulating substrate while keeping the piezoelectric element in a non-contact state with the insulating substrate; A thickness-shear piezoelectric vibrator characterized in that the conductor pattern is electrically connected to the conductive pattern via the anisotropic conductive adhesive. 2. In claim 1, the anisotropically conductive adhesive contains spacer particles that establish a distance between the piezoelectric element and both of the insulating substrates. Piezoelectric vibrator.